Bitcoin is the new payment technology but, it will don't make banks disappear. In the coming days, banks will understand the usage, advantages and technology of Bitcoin and implement in various payment methods.
I agree with you, that will be the possible scenario for bitcoin and also the banks because if the banks will realized that bitcoin is worth it then there is no reason to not adopt it as a good payment method for their banks deposit and also for withdrawals and acting as an exchange for bitcoin to fiat or vice versa. Banks will adjust because they can't stop bitcoin because it is decentralized currency.
Whether we like it or not, banks are there for profit. And if there are more additional profits they can get from incorporating bitcoin services into their business, then there is really no reason for stopping that. I believe that they are just keenly watching and observing how this new bitcoin phenomenon and it is just a matter of time that they will soon adopt it.