i don't think centralized exchanges are going anywhere or even changing in the future. they may become more secure but that would be about it.
at the same time decentralized exchanges will grow but as an additional option that you can use if you wanted to go that rout and needed the decentralization. but there is still a lot of downsides to them for example you can not trade with fiat on a decentralized exchange, it still remains easier to use centralized ones for that matter.
Of course, the inability to trade with Fiat is a minus for decentralized exchanges, but in the future, when cryptocurrency will be used as money and Fiats influence will be less than now, then decentralized exchangers will be more popular and in demand. Decentralized exchanges are the future and they will continue to exist.