With FTX happening and everyone screaming take your cash off exchanges (Which I’ve completed a very long time in the past) what would happen if for example there have been no exchanges left if that may even a attainable? Please remember that I get the actual fact we might love fiat to utterly get replaced by crypto in the future.
If no exchanges were left, anywhere, then we must have been invaded by aliens, who have instituted a totalitarian, planet-wide government, and basic freedoms abolished.
An exchange is just a place where individuals can meet to exchange various goods, property, currency. Sometimes government currency is involved, other times it’s barter/swap/like-kind/differing-kind.

Supply and Demand.
If people need exchanges but none exist, new ones will be created, because there is money to be made.
Peer to peer.
Since you need a way to off-ramp your crypto into fiat an exchange will still be required. That’s why we’re all pushing for DEX over CEX. Decentralized exchanges are the way to go.
I just wish there was ONE exchange that wasn’t a speculative money moving bad investment hedge fund nightmare.
People would realize how confusing and risky doing any type of transaction with crypto is and the entire charade would come to a halt, and crypto would return to its original use of anonymous transactions for illegal purposes.