What has happened is unprecedented on any scale. Simple as that. The set of regulations that might have prevented this might well put a serious damper on US economic growth.
As for regulations, I expect we will see securities firms like Bear get regulated by the Fed in the future. Kind of goes with giving them access to the discount window, IMO. But beyond that, exactly how do you propose to regulate private companies? What jurisdiction does the Fed and the SEC currently have over private partnerships domiciled offshore (i.e. hedge funds)? Unless Congress passes some very different laws than we curently have, I don't see it. If they do pass such laws, the US is likely to lose a lot of financial services jobs and GDP (and I might well end up working in London, Bermuda, etc.). In any case, regulations are always made to be arbitraged/gotten around, so its only a matter of time before creative people find new ways to blow themselves and others up in size.
Are you talking "economic growth" in terms of "sustainable improvements in the number of widgets produced per hour of labor"?
or do you mean the boom portion of periodic boom/bust cycles? I like the first but not the second.
I'm sure that the gov't currently regulates every private company in the US that hires workers, so I don't think that regulation is impossible.
The question is whether it does more harm than good.
If an electric utility is putting up a power plant in my neighborhood that could blow up and kill us all, I think it would be okay for the gov't to force them to change their design.
If that means more expensive power, that's a trade-off we'd probably make. (I would want to see a cost/benefit using reasonable probabilities of the explosion first.)
So the questions here are
"What's the exact mechanism that can turn an ordinary bankruptcy of a middling sized firm (14,000 employees) into a complete meltdown of the US economy?"
"Where is the most efficient spot to change the system to prevent that from happening?"
"How much real, sustainable economic growth are we giving up if we mandate that change? and how much does that reduce the chance of a meltdown?"
I really don't care if a few jobs go overseas (sorry, but remember you'll still have internet access) if the value of what we gain is more than what we lose.