Financial dinosaurs haven’t gone extinct. They have just gotten bigger.

Two decades ago, Bill Gates described banks as "dinosaurs" that would be bypassed by innovative technology. Yet since then banks have survived challenges from personal-finance software, early virtual banks and the Internet. Now, there again is talk about banking being disrupted. Money is pouring into financial technology start-ups. The initial public offerings of LendingClub and On Deck Capital were wildly successful.