(BTW this ignores the fact that banks have huge political influence and will support any political attempts to block the advance of bitcoin.)
I think there's a good chance (mmm... 65.3%) that within 4 years one or more of the largest 1,000 US banks will support currency exchange to/from bitcoin for their customers.
Why would bitcoin be a threat to banks? They're really good at securely handling currency; that's a valuable service, whether the currency is dollars or euros or bitcoins.