Not possible life without bank because many people need to borrow money from the bank and make their business, not available for borrowing in bitcoin and altcoin and then not have institution available for every one could borrow bitcoin or altcoin, now day many country have several bank kinds and give good service for every one to save their money.
Yes its not possible for now because banks has a participation to our economy to boom. Its like a cycle giving and taking. So crypto and banks will co exist and that would be beneficial for us right? There's no need to get rid the banks because its essential part of our lives and economy.