I think it can be possible and in future can happen, but i think governments will still want bank to work and this is the way they control money, but will be great if will be possible to use only crypto, now when i want to cashout crypto i need to work with banks.
It is possible but it is very hard. Even if you have a lot of Bitcoin, it will be a problem to find the places where to spend them. In the future, this problem will disappear, and BTC will be used widely.