Cannot, the bank is the official institution that full supported by the Government's, all done through the bank such as economic policy. bitcoin can't possibly eliminate and make the bank disappear even though used en masse.
Correct and also the goal of bitcoin is not to make banks disappear, the goal of bitcoin is to allows to have an alternative to the banking system and that is something we can do already, although with some difficulties but as time passes it will become easier.
But this time more users will makes bitcoin as their primary investment than banks, because we can see the opportunity to get much better income by putting money in bitcoin due to faster increase of value unlike in the bank you money will increase too slow because of lower interest of your savings.