BCH wont vanish but it also wont overtake BTC (will have its ups and downs based on mining profit but won't go above BTC at any point)... Segwit 2x is almost 100% not going to happen (no Nov hard fork) due to segwit being patented by blocksteam (a company which is FOR the current segwit chain and is AGAINST the segwit2x chain).

That being said all this crap will make BTC and BCH prices fluctuate a fair bit over the next few months, but if you had to bet one 1 horse in this race (BTC vs BCH vs XBT) in my strong opinion you would defiantly want to be betting on BTC for the win... just my 2 satoshi's!