I suspect those who didn't were mostly the ones with deeper insight of the underlying technology. When the fork occurred full blocks had already been a problem for well over a year. Segwit was not the solution and overcomplicated the blockchain. This is not debatable anymore. Bitcoin Cash abolished this "overengineering" and simply increased the block size. Disabled RBF making 0-confirmations a thing again. And lastly just recently fixed the DAA. Many think that Bitcoin Cash is closer to the original whitepaper by Satoshi. I'd argue that is true.
Currently the Bitcoin has had 100k+ unconfirmed transactions for weeks... and a ever growing mempool. You cannot transact or move your coins confidently without paying large fees. 500 satoshis/byte or about 30 dollars. The original vision is completely destroyed. Sentences like "store of value" are now the term used to describe Bitcoin. Very far from what the Bitcoin used to be. https://bitcoin.org/en/ is little more but a lie now.
I know this is not a valid reason to say that increasing the block size is the only solution. Of course there are other solutions. One is segwit... but that has not solved anything at all. The thing is that increasing the block size would fix Bitcoin's problem right now. Compare segwit implementation with increasing the block size. Segwit is a very complex implementation and frankly I would call it over-engineered. Worst. It hasn't done ANYTHING for Bitcoin. Currently the Bitcoin has had 100k+ unconfirmed transactions for weeks... and a ever growing mempool. You cannot transact or move your coins confidently without paying large fees. 500 satoshis/byte or about 30 dollars. The original vision is completely destroyed. Sentences like "store of value" are now the term used to describe Bitcoin. Very far from what the Bitcoin used to be.
To me it seems much more likely that another, unrelated cryptocurrency will eventually fulfill the role BTC was originally intended for.
People do "more" when stuff gets easier for a lot of other things.
But if you want to drill down on this specific situation, think about how many "newbies" must have come to Coinbase because of the recent Bitcoin surge. They weren't using any other online wallet or exchange - just Coinbase. And now suddenly they have an extra cryptocurrency option. A lot of them will try it out, thus increasing the price of the coin.
This is also exactly why Bitcoin is maintaining a leadership among cryptocurrencies and will for the foreseeable future, despite being so much worse in many areas compared to newer cryptocurrencies. Bitcoin is the "de facto" cryptocurrency accepted not by 50%, 70%, or 90% of the crypto exchanges out there, as some of the other cryptocurrencies are, but by 100% of them.
Also, all the other cryptocurrencies are exchanged into Bitcoin. There are very few other cryptocurrency "markets" other than Bitcoin. Some exchanges support turning your other cryptocurrencies into Ethereum for instance, but not all of them, and even for those that do, people still prefer to exchange into Bitcoin.
The "first mover advantage" is very strong here, and Bitcoin will continue to benefit from it until maybe every other cryptocurrency is 10-100x better than Bitcoin in every way and everyone will wake up one day and say "wait, why are we using Bitcoin as the default currency again?!" But it's not a guarantee that will happen soon, or even ever.
Well now you know. Speaking for myself, I can't be bothered to upload my ID to another exchange again. I probably should because I haven't been able to send money to Coinbase in forever but eh. Coinbase is very simple to use, and you should never underestimate the value of convenience. It's one of the things that made Amazon as large as it is today.