Lost in all the petty bickering above is any common sense discussion of what did or did not happen to bankers.
In our system of justice - in fact nearly all systems of justice - you only prosecute (not persecute) and imprison a person who has knowingly committed or intended to commit a crime. So, you go to jainl for knowingly taking a car that does not belong to you, or for knowingly selling or possessing a pound of heroin, or for knowingly withdrawing money from someone else's bank account and spending it on yourself. On the other hand, if someone plants heroin in your car without your knowledge, you do not go to jail for possession of drugs because you did not knowingly possess the drugs.
Certain crimes allow a lower mental standard that knowingly - like recklessness. So, if your drive your car through a playground at 80 mph and kill a child, you go to jail even if you did not intend to kill a child and even if you swerved to avoid the child. There was a high probability that driving 80 mph in a schoolyard would result in injury or death, so doing so showed a reckless disregard for the value of human life. You go to jail.
There are also some types of crimes where simple negligence will get you punished. However, the types of crimes are administrative in nature and are usually punishable only by monetary fines, not imprisonment. So, for example, if your company through negligence fails to properly maintain pollution control devices at a factory and you emit more soot into the air than the EPA permits, your company gets hit with fines, but nobody goes to prison. So, if an engineer misreads a specification and buys the wrong filter, neither he nor the company CEO goes to jail. Which is fair and smart - otherwise no one would every take those jobs and we would all be screwed.
In the financial sector debacle, a lot of banks execs mad bade decisions. But that was mostly because even they do not fully understand everything that goes on in financial markets. A lot of execs make decisions based on what worked for other banks. So, if Bank A makes a lot of money bundling and selling mortgages, then surely Banks B, C and D will try the same thing.
And, it works. Until one day it doesn't.
And then when companies go broke, everyone wants to point the fingers and demand that SOMEBODY go to jail. But that is nothing more than making someone into a sacrificial lamb. It accomplishes nothing.
This isn't too say that no one KNOWINGLY did wrong. I'm sure there are a lot of instances where somebody hid bad financial reports from investors in violation of the law - or something similar. But that is something that can only be attributed to the individual in question and it must be proved in court - beyond a reasonable doubt.