What would happen to Bitcoin’s value if all countries banned crypto exchanges together ? Can it survive such an action ?
This question would hold relevance many years ago when bitcoin was still very early especially when that mt gox hack happened and most recently, the FTX collapse. But since bitcoin didn't stop there, those events alone should be able to answer your questions.
Fwiw, even if exchanges are banned, there would be ton of decentralized solutions that would come into play.
I bet if that scenario where exchanges are banned there will be surge of P2P platform appear and people gonna just do what they're doing back then when we're still on the early bitcoin days.
Just do transaction with other peer and build reputation system.
These exchanges are 100% replaceable in that scenario where they are suddenly dysfunctional.