Banks will change or go under but they won't go away. They will always find some service to provide that someone else will want to buy.
No it wont happen. Bitcoin will never make bank disappear even it has a big value or importance because banks are all manage by te government and all people agree and accept it unlike to coins that bot everyone knows it. Banks will still remain and bitcoin was just in the virtual world. Bitcoin was just give contribution to the banks but it cant make it disappear.