> There aren't any criminal prosecutions because it's hard to prove that there was fraud.

No it's not that hard to prove their was fraud. It just takes forever to bring up Federal Grand Juries for some many cases of fraud.

The Fed Grand Jury I was on one was dealing with financial crimes from 5-6 years ago. They had so much evidence. My lesson was that only the big fish get fried in federal financial crimes, because everyone else gets immunity to compel their grand jury testimony. (if you can't be prosecuted you are unable to take the 5th and remain silent -- you must testify)