They can change or can work with bitcoins.
but they will never disappear as fiat will never disappear too.
If fiat comes to the point that has no use already,
then thats the only time that banks can disappear.
But as i have said, its impossible.
Yes I believe it too that banks will never disappear as long as the community are still using fiat on their daily life. Not everyone are using bitcoin these days and I believe fiat and bitcoin can co exist together. Maybe bank will disappear if the government will permanently remove fiats but i don't think its gonna happen anytime soon.