I don't think the market for DEX will vanish even if CEX implements most of its features. Unless CEX somehow allows non-KYC/registered users to trade or replicate the DEX login-less feature (only using a web3 app like Metamask), DEX will still exist. If that does happen though, it will be interesting to see how long it will last, unless they are registered in some obscure location that has no laws (which is likely a scam anyway).

Personally, giving up personal information is one of the key reasons why I find using a new CEX a terrible alternative if one of my main liquidation methods/trading platforms breaks. I'd still use DEX or P2P even if most of the features I need are provided by the new exchange.