I doubt that banks will disappear in the future, I think that there will a mutual benefit between banks and blockchain technology. If the banks disallow transaction between fiat and crypto then financially cryptocurrency is useless for it is not so established that much. I think the banks will evolve for years to come and speed-up every transactions same to other establishments.
That can last for some time that is true but at the end bitcoin will become a replacement for the banks, some people are already using bitcoin for all their purchases despite the lack of adoption , what do you think it is going to happen when bitcoin can be accepted in almost every store in the world? People will no longer see any need to convert their bitcoin to fiat and that will be the moment when the banks will be at a huge risk of disappearing.
You can doubt in crypto, but in the end crypto will replace banks. I don't see any other outcome. Peoples didn't have alternative like they have now with crypto, first wave was all about people and from people to people, next wave will be when small and medium companies adopt it, they wish to skip using banks to and to find direct line to customers, that's what they need, and third wave will be heavy industry adopting crypto.
Banks will be a thing of history, sooner or later is hard to say. I see that for a long time, since I'm here. Maybe I didn't believe in that from first days, but after a while I started to and I didn't stop until now.