Much of this falls on the Government trying to get every Tom, Dick, & Harry into a house, regardless of whether they could afford it or not. There's no question the Government and the Fed encouraged banks to lend and bundle. The bundling is what kept the reckless lending going for so long. There were plenty of defaults along the way but they never came to surface because they were minimized by quality loans. Then the shit hit the fan....
Quote from telozo:
The problem goes deeper than a crooked rating agency giving repackaged junk AAA ratings.
It all starts, and I am amazed that a lot of very articulate people around here miss that entirely, with government trying to play the paternalistic role more than necessary (read Milton Friedman for more info on government's role in the society). It all starts with some pension funds losing money to some crooks, and government deciding to protect all other pension funds from that happening again. The easiest way is to regulate, and a regulation is passed that pension funds can only invest in AAA-rated securities. But rates are low and not may AAA-rated securities are around to generate good returns, so the pressure is on to generate more AAA-rated securities, and Wall Street is happy to oblige, and rating agencies are playing along, and everybody is happy until the shit hits the fan.
It's really very simple, even though counterintuitive - less regulation is better than more. Sure, there will be dead bodies along the way, but no major disasters, and that is the best that can be done.