Even at it's core, though, it's the fact that the government allows the corps to play a sort of "manipulate the system" game, where they don't have to cover their asses because they can externalize all the losses.
I think, economically, the best sort of regulation is the type that internalizes those losses, so people can't game the system by pushing the risk off onto someone else - more regulation (and better, current stuff is often all to easy to avoid) of that sort would have held those who gambled and lost responsible for the loss, and would have gone a long way towards preventing them from making ultimately unsustainable bets to begin with.
The big players here, the ones who were really responsible, almost all knew they were going to lose, and lose big, eventually - they were just absolutely sure they wouldn't have to deal with the fallout, and their immediate profits would more than offset any minor portion of the cost they might have to actually deal with. And if they didn't, hell, it's not like the government could let them fail, right? It would blow up the economy!
A classic "Heads I win, Tails you lose" sort of situation. And regulation could have prevented it. (As always, the difficult part of regulation is preventing THAT while still allowing the bits that are actually productive and good for the economy)