A tale of Two Coins

In 2005 Michael Burry discovered that the mortgage back securities that banks were selling to investors had included in them mortgages that were delinquent. This he recognised to be a fatal flaw and as history would record, he successfully engineered a long term bet against those securities in what we know today as "The Big Short".

That there were delinquent mortgages in a package of securities was not unknown. The idea was that returns from the good mortgages easily covered the small losses from the bad. The problem however was that there was an insatiable appetite for these products and investors were willing to accept ever higher level of risky mortgages in their basket, to the point where these sub-prime mortgages were "manufactured" to supply the demand. Investors drew comfort from the widely held but faulty notion that house prices will keep rising and the property market will never collapse. They were wrong, and we are still living the result of that folly, with nearly 10 years of recession/depression.

How is this relevant to Bitcoin?

In a previous article I pointed out that as a result of Bitcoin Cash, miners now have the option to mine BTC or BCH. Bitcoin without the Emergency Difficulty Adjuster (EDA) is vulnerable to a massive drop in hashing power which would lengthen the time between blocks to hours such as happen to BCH at the time of the fork. This is a disaster that BTC would never recover from because it does not have the protection of EDA.

The Bitcoin mainstream refused to acknowledge this, postulating that it would never happen and that miners will never do that. But that is not the point. The question is not if miners will or won't but if they can or could, and if it is the latter, then there is a non zero existential threat to the universally held notion of the indestructibility of Bitcoin. Investors who hold bitcoins as a store of value can wake up one morning to a black swan event that renders the value of their nest egg to zero. Projects and start-ups dependent on BTC holding value will collapse and fail.

To make matters worse BTC is also limited to 1MB blocks. This means that if only a fraction of mining power is lost to the bitcoin network, block time lengthens and the mempool bloats. Without the benefit of big blocks to clear the backlog, transaction fees increases to the point where the bitcoin blockchain becomes unusable, except to those willing to pay usurious fees.

Long block and block maturity time will drive miners to mine the BCH chain which is already more profitable. This causes a feedback loop which will inevitably lead to the dreaded Chain Death Spiral, and the collapse of the Bitcoin blockchain.

To argue that the BTC blockchain is more profitable to mine if higher fee rewards are taken into account, is oxymoronic to the extreme. It is the argument of a bias and disingenuous supporter or a greater fool. The fees are high precisely because blocks are small. Pinning their hopes on Segwit and/or 2MB is hopelessly inadequate and unrealistic for a technology that is on the cusp of explosive growth and mainstream adoption.

The time for action is now.

We must now confront the reality that Bitcoin has not 1 but 2 fatal flaws. EDA and 1MB blocks. The effects of the 1MB block is already evident with the mempool consistently over 45MB and a blockchain that is becoming increasingly unusable. In all probability, the Bitcoin blockchain is kept alive only by the good graces of miners honoring their increasingly untenable NYA agreement.

Why has there been no discussions of these fundamentally important and critical issues? The answer must be fear and greed. Fear that any such discussions will lead to the fall in the bitcoin price or a move to Bitcoin Cash. However, censoring and avoiding discussions purely out of greed is downright fraudulent. We have already seen what happens as a result of greed replacing reason in the sub-prime disaster. Not to address this "elephant in the room" may lead to a total loss of confidence by the public and ridicule by governments and banks, eager and waiting to regulate and control.

A new market quoted pair for Bitcoin Cash.

The market capitalisation of Bitcoin Cash is in excess of 10 Billion and rising. Many investors are now aware of the problems inherent in Bitcoin and have opted to move or hedge their position with Bicoin Cash. Herein lies a problem. The value of Bitcoin Cash is pegged to Bitcoin. What happens if the price of Bitcoin goes to zero? We need a contingency plan now. Bitcoin Cash should be traded and reported as currency pairs side by side against BTC. We must demand and insist this of the exchanges. This way if BTC fails the process of transition is seamless.

Contrary to popular misconception, Bitcoin Cash is the real bitcoin, and it was not a new fork, but a fork back to the original. In just two weeks it has taken the number three spot in market capitalisation and will soon replace Ethereum at number two. In the process it has eroded the value of all alt coins that have gained prominence because they were allowed to exploit their specific niches by eroding use and value from Bitcoin. The community is sending a message. Loud and Clear.

It is high time to put BCH back where it belongs.

Related Articles

Bitcoin Cash Will Regain The Mantle To Be Bitcoin - Here

Why is Bitcoin Price Rising - It May Not Be What You Think - Here

Bitcoin Fork - Smoke. Mirrors and a good game of Poker - Here

Chain Death Spiral - Here

Bitcoin Cash (BCH) Will Regain The Mantle To Be Bitcoin

Here Is Why

                          BTC      BCH       TOT        BTC     BCH         BTC       BCH         BTC
                           ( Hash Power )                   ( Difficulty)           ( Block Time )    (mempool)

11 August            6600      338       6938         923        115       10.00         21            55
12 August            6199      416       6615         923        115       10.66         20            15
13 August            6808      440       7248         923        115         9.73         18.46       27
14 August            5951      522       6473         923        115        11.07        15.82       47
15 August            6966      647       7591         923        115          9.47        12.85       53
16 August            5984      484       6468         923        115        11.07        17.14       50

• Since 11 August Hash Power on the BCH chain has increased daily.
• Hash power on BTC chain on the other hand fluctuates from day to day, by up to 1000 PH and the mempool continues to grow.

The table above are snapshots taken at a point in time each day. Their individual states can be monitored in real time here*.  Scroll down to the hash rate. BTC hash rate is down to 4853 PH. This is more than 2000 PH below the table above and the mempool has now exceeded 65MB. I truly believe that the dreaded Chain Death Spiral has set in but is being "managed".

This large fluctuation of BTC hash rate could be the miners preventing difficulty from adjusting downwards, and at the same time growing the mempool. It is also possible that with over 1000 blocks to the next difficulty recalculation, we may not see another difficulty adjustment on BTC anytime soon.

It is uncanny that we see very little discussion and debate at the very top. It is as though the NYA agreement have settled everything. However make no mistake. What seem calm belies what is happening in the background. Like a duck on the water paddling furiously underneath.

Over at r/bitcoin talk seems to center around price and technology. Nothing about any negativity, usability or the growing mempool. Censorship of robust discussions is just downright deceitful. Especially if it is the de facto forum. It must quit being a propaganda organ. There will be consequences.

Undoubtedly the people around Segwit must be frantically on the phone, fax and email arguing and pleading with the miners. They can see the writing on the wall. Only 124 blocks were found in the last 24 hours. Block time have increased to 11 minutes and the mempool is in excess of 70MB. It is "too little too late". For many of the miners "Revenge is a dish best eaten cold".

Here is why Bitcoin Cash (BCH) Is The Real Bitcoin

It is the original bitcoin
It was hijacked from Gavin Andresen very surreptitiously by Adam Back with his Sidechain proposal. It was a "Trojan Horse" and together with the help of Blockstream, Theymos and the Core developers the process was completed. We the original community have finally regained control of the Bitcoin project, except that we have lost control of the name. This position is about to be redressed.

It does not have Segwit.
If you look at a Bitcoin file as AD. A being the address and D being the data, Segwit removes the address portion A, It is reduced to a hash and the original signature is discarded after it is verified. So if your "fingerprint" is the hash of all your signatures, the signatures are discarded after being checked, and only the "fingerprint" is kept. This is in effect what Segwit does.

The signatures are stored on another chain, but not the main chain. Some nodes will keep signatures, some only keep partial records, some will discard them entirely. If you ever need to refer back to the transaction to check on the signatures all you have is the hash. "The fingerprint". Satoshi's original design of bitcoin being an unbroken record of signatures is violated.

It allows for unlimited on-chain scaling.
A clear example of the disastrous effect of limiting the blocksize is the state of BTC now. The mempool is huge and getting bigger, fees are "over the top". Their intention is to push low fee transactions to side chains and the lightning network. These solutions don't exist yet.

The Core developers bought themselves over 2 years delaying and obfuscating on chain scaling, and yet have no working solutions. Meanwhile the user experience gets so bad that many users have sought other alternatives to transact. BCH in the meantime have mined an 8MB block.

It has more client implementations
BCH will have Bitcoin XT, Bitcoin Classic, Bitcoin Unlimited, Bitcoin ABC and more. Each with their own development team but all operating on the same chain. This diversity increases security, innovation and development of the whole ecosystem.

The part played by nChain in this saga should not be discounted. Without a doubt the most interesting improvements in Bitcoin is coming from nChain. Split Keys, Turing completeness are major developments. Whether you believe Craig Wright is Satoshi or not, there is no doubt he is the brightest and most fertile mind in the Bitcoin space, and he does not support Core and Segwit.

BCH survived, and that is all it needed to do

Bitcoin price is at an all time high, but it is not reflective of its' true value. Many people have been duped to sell their BCH without knowing the true state of affairs between BCH and BTC. Newbies entering the ecosystem have no choice but to enter through BTC. The price increase and media hype also drives more people to buy in at any price because of the fear of missing out. Please share this information to give everyone as much true information as they can before they part with their hard earned savings. For those who have missed out on $300 bitcoin, this is a second chance. BCH now has half the transaction volume of BTC but less than one tenth the price. BCH will be worth what BTC is now and more. I do not think the public will turn away from bitcoin if BTC crashes and BCH took over. Bitcoin will change the world and it is here to stay. We are only at 1 million and there is still 6 billion to onboard.

* Unsure of the accuracy of this but can be double checked on Blockchain.info

Related Articles

Why is Bitcoin Price Rising - It May Not Be What You Think - Here

Bitcoin Fork - Smoke. Mirrors and a good game of Poker - Here

Chain Death Spiral - Here

BTC is Dead - Long Live BTC - Here

BTC is Dead - Long Live BTC Updated and Explained ELI5 - Here

Why is Bitcoin Price Rising. The Answer May Not Be What You Think.

Greater adoption especially in Japan. True.
Higher prices leading to greater interest and media hype. True.
Large investors and hedge funds investing. Also True.
More people trust the Core developers. Perhaps True.
Segwit is locked in and will activate soon. Maybe True.

But what if the people in control allow it !?

So who are these people in control? They are the people who simply by their action will affect the price. No, not the market manipulators as their desired results are not guaranteed and effect only temporary. No not the developers or even users. I am talking about the people in control of the hashing (mining) power, and by their action supporting or withdrawing their hashing, affects the success or failure of a chain.

For the first time in Bitcoin history. if the miners withdraw their mining power from mining BTC, transactions on the BTC chain will grind to a halt. ( See Chain Death Spiral ) Block confirmation time will be exceeding long and user experience so bad that BTC's price will collapse. Just the announcement that they will do so is enough to affect the price negatively.

So why have they not done so before? Well, prior to the fork, they will only hurt themselves as they mine and hold BTC. Today they have another option. When this strategy plays out, their plan will make them all the money that they have dreamed about.

Some of the miners with about 40 percent of the mining power have fought a very bitter battle for big blocks over several years. It was a very nasty, very open spat with both sides spewing verbal diarrhea on social media. This will not be settled by just a simple agreement and bear in mind that none of the Core developers were present or signed the NYA agreement.

We hear justifications like :

• Miners mine the most profitable coin. True, but this is economic action not strategy.
• Miners will honor their agreement. Money talks. Everything else is just noise.
• Segwit and BTC is better technology. Better technology does not always win. 

Core developers are not the same as the army of programmers and developers pulling for Segwit and Side chains and Lightning. I cannot fault their passion, zeal and dedication. However they are just being used to push an agenda.

Core developers do not want Segwit2X and have openly said so even coding to exclude Segwit2X transactions. They did not expect the BCH fork, but even so, are perfectly happy with BTC as it is, even if it loses to the other chain. There will be no Segwit2X. Simply put there are no developers for Segwit2X. Core developers will not be coding for Segwit2X.

The Big Reveal.

This is the Rich List as at 13 August 2017. The numbers may not be 100% accurate but they do paint an unmistakable picture.
                                                      BTC      BCH                        BTC            BCH
                     10000 - 1000000     121         121                        3011886      3310777     +298891
                     1000  -  10000         1666       1688           +22     3544974      3635319      - 90345
                     100   -   1000           16594     16160        -434     3840815      3726874     -113941
                     10   -     100             129880   122874    -7006     4344270      4183607     -160663
                     1   -       10               464743   424298   -40445    1277766      1163236     -114530

Most of the BCH coins about 300K have been gobbled up by the top bracket of 121 addresses. If BCH and BTC flips at current valuation, it will mean a windfall of just over 1 Billion dollars now. When this finally plays out, it will make the "Big Short" look like a pauper's picnic.

All the rhetoric encouraging BTC owners to sell their BCH for BTC, and media hype pushing up BTC price helps their strategy, without them lifting a finger. All that is left to do is switch the chain when they are right and ready. Don't get caught on the losing side.

P/S Please share. Help your fellow bitcoiners get the best information before they make the investment of their future. Fear Of Missing Out especially now can lead to unwitting mistakes and losses.

Update 15 August 2017

                          BTC      BCH       TOT        BTC     BCH         BTC       BCH         BTC
                           ( Hash Power )                   ( Difficulty)           ( Block Time )    (mempool)
31 July                 6163                                    860                    
1 August              6440     1525      7965         860        860        9.66        160              5
2 August              6433      378                        860        860        9.47        205              5
3 August              5931      447                        860        860      10.43          41            10
4 August              7749      216       7965         860        225        8.04          75            23
5 August              7473      143       7617         860        225        8.13        110              5
6 August              6023      499       6612         860        114       10.28         22              3
7 August              6637      551       7188         860        114         9.41         18            33    
8 August              6835      154       6989         923        115         8.78         62            35
9 August              6200      541       6741         923        115       10.43         15            43
10 August            6165      576       6741         923        115       10.74         14            42
11 August            6600      338       6938         923        115       10.00         21            55
12 August            6199      416       6615         923        115       10.66         20            15
13 August            6808      440       7248         923        115         9.73         18.46       27
14 August            5951      522       6473         923        115        11.07        15.82       47

Floating                                           1492

14 August - Hash Power on BTC reduced to 5951 PH and increased on BCH to 522 PH. The BTC chain is starting to slow, with mempool at 47MB and Blocktime 11.07 minutes. It will be interesting to see if the hash power increases tomorrow.

The amount of 1492 PH in red is the difference (7965 - 6473) between the highest recorded and today. That amount of hash power exist but is not on the network. Somebody controls it. Watch what they do with it. BCH price is rising (0.072) as the BCT chain gets slower. Let us watch as BCH retake its' position as the Real Bitcoin. More To Come. Keep Sharing.

Bitcoin Fork - Smoke Mirrors and A Game Of Poker

In this article I present the facts as I see them and leave it to you to reach your own conclusions. My opinions are my own and I encourage you to do your own due diligence. I could be wrong. It is your hard earned money.

Rehashing and analysing the figures over the period of the fork it is clear now that Bitcoin Cash had a difficult birth. Looking back I am convince that it would have been highly unlikely to succeed. I think what eventually happened was planned and executed by persons unknown who clearly wanted Bitcoin Cash to succeed. The key is to analyse the available hash power and look at how it was applied.

Refer here to Jimmy Song's article on how the Emergency Difficulty Adjuster (EDA) kicked in. Before it can be activated at least 12 blocks must be mined! ( The UAHF specifications. Starting block 478557.)

The First 12 Blocks
                                                     ( Approximate Time Lapse between blocks)
August 1st 2017   AM  8:16:14
August 1st 2017   PM   1:12:41     4 hours 56 mins
August 1st 2017   PM   1:33:06                  21 mins
August 1st 2017   PM   1:37:19                    4 mins
August 1st 2017   PM   1:52:58                  15 mins
August 1st 2017   PM   2:37:44                  44 mins
August 1st 2017   PM   4:05:15      1 hour  28 mins
August 1st 2017   PM   4:35:44                   30 mins
August 1st 2017   PM   4:39:21                     4 mins
August 1st 2017   PM   6:38:29      1 hour   59 mins
August 1st 2017   PM   8:07:01      1 hour   29 mins
August 1st 2017   PM   9:51:49      1 hour   44 mins
August 1st 2017   PM  10:15:01                  23 mins

Looking at the figures I would say roughly there was about 1 hour between blocks. At the same difficulty of BTC's 6500 Peta Hashes producing 10 minute blocks, we will need at least 1/6 the hashing power to produce 1 hour blocks. That is about 1200 Peta Hashes.

                             BTC     BCH    TOT           BTC     BCH         BTC       BCH         BTC
                               ( Hash Power )                 ( Difficulty)           ( Block Time )    (mempool)

31 July                 6163                                     860                        
1 August              6440      1525      7965         860        860           9.66         160              5
2 August              6433       378                        860        860           9.47         205              5
3 August              5931       447                        860        860         10.43           41            10
4 August              7749       216       7965         860        225           8.04           75            23
5 August              7473       143       7617         860        225           8.13         110              5
6 August              6023       499       6612         860        114          10.28          22              3
7 August              6637       551       7188         860        114            9.41          18            33        
8 August              6835       154       6989         923        115            8.78          62            35
9 August              6200       541       6741         923        115          10.43          15            43
10 August            6165       576       6741         923        115          10.74          14            42
11 August            6600       338       6938         923        115          10.00          21            55


Prior to 1 August the highest amount of hash power recorded was on 24 July at 7118 Peta Hashes. This is roughly 1000 PH over total hash power on 31 July. We can therefore be sure that at least this amount of hashing power was available and at least 678PH was "floating" and withheld from the system. The maximum hash power ever applied to the BTC and BCH chains was 7965 PH in total on 4 August.

We know we need at least 1200 PH mining on the BCH chain on 1 August to find the first 12 blocks. From the above table we can see in red that there was at least 1500 PH available and I believe this was directed to mine the BCH chain. Without this input, it would have taken about 3 days to mine the first 12 blocks and the BCH chain would have been a failure.

The Morning After

Once EDA kicked in, the BCH chain is assured of survival. The next objective is to get the block time down to 10 minutes and profitable mining as soon as possible. Or is it? Hashing power was taken off BCH chain on the 4 and 5 August to trigger the 6 blocks difficulty reductions and again on 8th August for 1 additional reduction The BCH chain was left at 15 minutes about 4 blocks every hour.

In addition on 4 and 5 of August about 7500 PH of hashing power was applied to the BTC chain. Was this done to push up the next difficulty adjustment to 923G on 8 August and possibly higher at the next difficulty adjustment? (Bitcoin Wisdom)

This "floating" 1500 PH was withdrawn on 6 August. As of 11 August there is still at least 1200 PH of hashing power "floating" and withheld from the system. So who is this mystery miner or miners? What is their intention ?

The Aftermath

We can see that on 9 August about 600 PH was withdrawn from the BTC chain pushing the block time above 10 minutes. The result is that the BTC chain is clogging up with low fee transactions and the mempool has already reached 57MB. Only those willing to pay high fees can get their transactions processed. Unless there is a fast injection of mining power this chain is in trouble! It does not have the protection of EDA and the Chain Death Spiral can easily set in if not already started.

Voila as if by magic, today, 11 August 500 PH was returned to mining the BTC chain and 250PH was taken off the BCH chain. This still leaves about 1000PH still "floating".

Over the whole of this period BTC stayed above $3200 and went above $3500 yesterday and $3700 today. All of Bitcoin mainstream was celebrating, attributing it to CORE and Segwit.

I believe that this celebration is premature. BTC rise could be the result of world tensions in regards to the USA and North Korea, a worsening global economy and gold not making any impact, The situation must be bad enough for investors to just ignore and overlook BTC's vulnerability. Currently BCH, which I believe to be the real Bitcoin, is selling at a bargain.

Beware Smoke And Mirrors

There is much going on behind the scenes. Nothing is what it appears. Hashing power is being used to influence and manipulate the market. The high BTC price is great for those wanting to sell their BTC and accumulate BCH. This will result in a major wealth transfer from those holding BTC to those holding BCH. I believe that the true Bitcoin will flip from BTC to BCH but that is just my opinion.

A Great Game Of Poker

In this game, very few people are showing their hand. The Bitcoin whales have gone into deep dive and have not been seen or heard from since the chain fork. When the time comes to show their hands there will be winners and losers. I think that the unexpected rise and strength of BTC price is a complication but it will not change the "game plan".

I can only present the facts as I see them and the conclusion I draw are my own. You could easily form a different opinion looking at the same facts but that is your right. In the end when the tide goes out we can all see who is without clothes.

In this environment I am guided by principles. The reality in Bitcoin is that there is no Government to rule and favour any faction or group. It is nature at its' purest. Only the strong survive and any weakness is punished. I believe in its' current form BTC has a vulnerability (No EDA) and that will lead to its' demise. Three months is a long time in crypto.

Related Articles

Chain Death Spiral - Here

BTC is Dead - Long Live BTC - Here

BTC is Dead - Long Live BTC Updated and Explained ELI5 - Here

Chain Death Spiral - A Fatal Bitcoin Vulnerability

Back in Bitcoin history, when Argentinian millionaire Wences Caseres ( Xapo, Paypal) came across Bitcoin he saw it as a potential solution to the periodic financial turmoil that totally wipes off the wealth of hard working Argentinians. In what I consider a very prudent act of due diligence, he paid a couple of hackers a sizable amount of money to hack and break the fledgling Bitcoin. Their conclusion was that it was unbreakable and that has remained true until today. The Bitcoin protocol has never been hacked. The vulnerabilities were the trusted infrastructure around it like the exchanges. The most memorable being MT Gox.

However on the 1st August 2017, Bitcoin main chain forked and a new coin Bitcoin Cash (BCH) came into existence. Some argue that it is closer to Satoshi's vision than the current Bitcoin (BTC) which separate the data portion from the address portion of the data structure. BTC became the main coin because it was supported by the majority of users, developers, Bitcoin businesses and miners in what is now knows as the New York Agreement.

Chain Death Spiral. (CDS)
After Bitcoin fork on 1 August it became obvious that Bitcoin the protocol did have an inherent vulnerability. This was that if the chain loses mining power it will have to wait a full 2016 blocks before the difficulty can be adjusted to bring the block time back to the normal 10 minutes. This vulnerability was never considered or analysed because until now the miners had no choice but to keep mining on the Bitcoin chain. After the fork however, the whole landscape has changed. Miners have a choice and power to influence the fate of the chain they are mining on.

This was brought clearly into focus when the blocktime of the BCH fork went as high as 15 hours per block in the beginning. BCH however was designed with Emergency Difficulty Adjustment (EDA) which adjusted the difficulty even before the 2016 block adjustment period is up. Bitcoin (BTC) does not have this safety feature and cannot have one unless a hardfork is performed to include it.

A Chain Death Spiral occurs when the block time increases leading to some miners switching chain. As more miners leave the problem gets worse and a feedback loop results in the dreaded Chain Death Spiral.

Bitcoin (BTC) mempool been increasing since after the fork on 1st August. It is currently 52MB which means it will take 52 blocks to clear without any additional transactions. The record was in May 2017 when it reached 120MB. The whole community was in an uproar resulting in a move towards other competing coins for transacting.

Looking at the hashrate distribution and starting from the 6th August we get the following


    (Peta Hash)         BTC         BCH       TOTAL  (Block Time)  BTC       BCH

6 August 2017        7473         143            7617                           8.13         110
7 August 2017        6023         499            6612                         10.28           22.15
8 August 2017        6637         551            7188                           9.41           18.46                    
9 August 2017        6835         154            6989                           8.78           62
10 August 2017      6200         541            6741                          10.43          15


A picture is forming. Between 8 to 10 August roughly 400 petahashes moved out of BCH which triggered the EDA adjustments then move back in. In addition there was a loss of 200 Peta Hashes on the 9th August and a further 200 Peta Hashes loss on the 10th August.

The current BTC mempool is 50MB and blocktime is 10.28 minutes. There is clearly a development and it will get clearer today. Will the 400 Peta Hashes leave BCH again or will the hashing power on BTC decrease further. What happened to the 400 Peta Hashes missing since 8th August. The BTC chain cannot afford further loss of hashing power. Its' blocktime must come back to within 10 minutes and soon.

What is certain is that the current price of BTC is not justified with this inherent vulnerability, risk of the dreaded Chain Death Spiral. Have investors totally abandoned any thought of immutable economic security and due diligence? It is incredible how we lose sight of the risks when we bamboozled with riches, hype and misinformation through censorship.

It is other peoples' hard earned money and other peoples' investments. Even the possibility that this "black swan event" can happen must be addressed. It should never be censored speech.

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Intelligent Comments

from coinsinspace via /r/Bitcoin sent 37 minutes ago

It's a textbook black swan because majority dismisses it automatically as impossible, yet it's unlikely but possible, and it would be very likely fatal.

If bitcoin was the only viable sha256 coin that would be a much smaller danger. In that case the mining power would have to completely disappear for long. It's much more likely if miners can switch, especially if the other chain is more profitable.

Once that happens there are several factors all accelerating the problem:
(1) Mining rewards can only be spent after 100 blocks. Normally that's about 17 hours. If 90% of mining power disappeared that would take a week. So that's a strong incentive to mine something else (if available) in itself.
(2) Bitcoin economy grinds to a halt, as transactions become increasingly impossible. This leads many people with coins on exchanges to buy other coins just to be able to transact, which lowers the price, making the alternative chain even more attractive for miners.

Which means that, as miners leave, the higher incentive the remaining miners have to also leave. In the event that almost all miners leave the difficulty reset never happens as chain dies.