I think banks will not disappear.
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.
I really like your view, it seems the bank will remain there, over time maybe later the bank will work with bitcoin, to facilitate us to transact digital money (bitcoin) that we will see later.