[Through deregulation, subsidies, lower interest rates, etc.]
Washington D.C. does not operate in a vacuum. It's sad, but apparently lobbyi$t$ have more influence there than the American people do. Not surprising though, especially given that a majority of the American people don't even bother to participate in the system.
Arnall and his merry band of thieving immitators scoped out weaknesses in the system and then systematically gamed the heck out of that system until the investors got wise to the fact they were being sold junk and pulled the plug.
Furthermore, the predatory industry lobbied hard to remove legislative obstacles that states had put in place.
You seem to be suggesting "well gee, the whole system is corrupt... we can't punish anybody".
I say we punish those who deliberately corrupted the system for their own benefit. It should be done as a warning to anybody else who has a head filled with "Enron MBA" inspired notions. Notions like, the creation of a corporate machine that systematically falsified data used to rate the securitized instruments produced by that machine. Notions like deliberately and consistantly ignoring your own lending guidelines and funding loans before red flagged appraisals were reviewed by your outside contracted reviewers.
Congress didn't come up with those bright ideas... the corporate employers of the lobbyists did.
I don't have a lot of confidence that anything at all will happen. I think we're somewhere past democracy and sliding towards tyranny in the cycle described by Plato in his Republic. Oligarchy over anarchy, throttled by the tyranny of the appetite.
[Nobody could start anything in Long Beach without someone out east (or maybe also Sacramento) giving the go ahead.]