In the 1920s, the Federal Reserve printed more gold-redeemable FRNs than there was gold in the Treasury. This caused an inflationary boom.
In 1929, they jacked up interest rates and caused a crash.
In the 1930s, there was massive inflation to bail out the banksters. The banks had huge profits while the rest of the economy was stuck in a recession/depression. This has absolutely no correlation with the massive bank profits that occurred recently.
Irenicus is correct in asserting that it is a vague thesis; but, I would also note, with an equally vague statement, that the UK never had a Great Deal either.