Other coins like BCH and others are just an act of creating clones of bitcoin by hard forking and claiming to be the original bitcoin.
But segwit 2x would definitely create some serious issues as it has majority miner support and it may replace the legacy bitcoin.If it does not has enough support,then another coin bitcoin segwit 2x would be created.
It has even support of more companies related to bitcoin.
How do you determine which one is original BTC and which one is clone? In case of BTC/BCH there were two identical blockchains. And even developers splitted to two different groups.
Only thing, that made it being "original BTC" was, that one blockchain contiuend under original BTC name, another one under new name. But they were identical. Same will go for a new hardfork.