I don't think so, banks are a very important part of the economical system right now, not just holding money but the act of receiving, lending, getting money+ Profit and giving the capital and part of the profit to the person.. The most important part of the cycle are the merchants getting loaned since this is the base for everything from real-estate construction, even to large companies.
If that's the sole reason why bitcoin cannot make banks disappear, then I think it's absurd since bitcoin can do all of that. It can be a huge part of the economical system too. Holding money? Sure. Receiving, sending, lending, getting profit? All of that can be done with bitcoins. And bitcoin is much more than that, that's why cryptocurrencies tend to succeed in the future.
Loans? Oh, that's easy too. Thinking that the other person might just run away? Don't worry. If we follow the same procedure (i.e. getting personal info of the borrower) and have a valid collateral, then no problem at all.