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.
yes, banks cannot disappear just because of bitcoin. Because there are many of people who didn't know bitcoin. Maybe bitcoin can now use as a bank for the bitcoin users but cannot replace different banks that we have.
in present time people are thinking that bitcoin cannot disappear banks yes that is right, but in modern time i think the trend of new generation is toward online business and shopping there i think most of the people will give preference to bitcoin and there the user of banks will reduce by the people and when all the people of the world will start using bitcoin then banks will totally disappear.