I think that banks will not disapper completely. They have a task to finance businesses. But I think that people will get more independed from banks in the future. Thanks to Bitcoin and others.
You have a point though but still people would really still depend on banks on the future hence its part of the economy and play an important role . Government would not allow that banks would disappear because they have a full control of it. Bitcoin would somehow be succesful on future regarding on online transactions.