Even though segwit2x backed down
Roger Ver then swooped in with BCash
People dont realize how much of an existential threat that posed to bitcoin
The nature of difficultly adjustments would have meant that if Roger has got majority hashing power (he almost did) then the bitcoin chain would have frozen, all miners go to bcash (except slush at 4%) due to increased profitablility
Bitcoin would have frozen and the difficultly adjustment would not have helped, as it would go into famine and feast like testnet. Miners hold off until btc mining gets 4x cheaper. Then mine a cycle of blocks and freeze it again.
The bcash supporters, rick, kim dot com, craig, roger etc. really were trying to kill bitcoin. A hard fork would have been needed to change the difficulty algorithm, for it to survive