ok i agree that currencies based on blockchain technology will have a huge affect on banks but i think banking system will stay alive for more centuries because there will be always people that prefers traditional old methods. so they will keep using banks.
Banks will be affected negatively due to crypto development but they also will save their position as well. They can't give up because they're supported by capitalist powers and share holders. They don't take risk against crypto development.
Their profit might be affected negatively as well.