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.
clear however that banks are really needed for everyone to make transactions that are clearly legal in the eyes of any country, not with bitcoin maybe only developed countries have made preparations to facilitate transactions.
a bank is an institution recognized by the state and all transactions can be accounted for at least there is a guarantee from the state for those who hold their funds in the bank not to lose it for any reason. not with bitcoin that is not guaranteed and because of mistakes and negligence we could lose, the state could not help to replace.
at this time the role of banks is still very much needed because all transactions can be done online as well as with bitcoin. but banks can penetrate to the small people whose transactions may still be manual.