When the Financial Crisis Inquiry Commission (FCIC) reported in January that the 2008 crisis was caused by lax regulation, greed on Wall Street and faulty risk management at banks and other financial firms, few were surprised.

That, after all, was the narrative propagated by government sources since 2008 and widely accepted in the media, in numerous books, and by many commentators. Writing in the New York Times on June 30, for example, Pro-Publica reporter Jesse Eisinger complained that bankers' concerns...