Jonah Goldberg argues that, even in the absence of regulation, we're a lot less vulnerable to another financial crisis because capitalists are good at learning lessons:

By now you’ve probably heard lame duck Senator Christopher Dodd thunder from the Senate floor (or myriad other locations) that unless his bill is passed we are just as vulnerable as ever to what happened on Wall Street. “Nothing has happened” that can prevent the exact same crisis from happening again.
Except that’s not quite true. Something happened: The crisis itself.
Think of it this way. We are just as vulnerable as ever to the threat of Coca-Cola releasing another New Coke. No laws have been passed to prevent it. No new oversight authority has been created to warn of its looming threat. And yet, the odds of Coca-Cola rolling out another debacle like New Coke are severely limited. ...
This is not to say that the financial crisis doesn’t justify any reforms. But let’s not forget that inherent to capitalism is the capacity for self-correction. Surely the disappearance of Lehman Brothers and the dismantling of AIG is an example that many can learn from. The real danger seems to me that people like Dodd haven’t learned the lesson that government is not the only—or best—corrective to the excesses of capitalism.

It is true that some of the capitalists paid a terrible price. But the vast majority of them did not. Because their collapse posed systemic risks to the entire economy, taxpayers were forced to bail them out lest they suffer even greater damage. The ability to enjoy all the gains from risky investment while socializing potential catastrophic losses is a fairly key variable here. This is rather different than the New Coke fiasco, the costs of which were born by Coca-Cola. Indeed, if anybody has "learned a lesson," it's the government, which learned that allowing even one firm (Lehman) to fail can have catastrophic consequences.