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.