While savvy investors may indeed underestimate low-probability risks, I take issue with any claim the mortgage bubble showed this. The sad end of that bubble was an extremely high probability event.
The main thing the debacle showed was the willingness of many people to believe fallacious arguments which made reference to claims about low probability events. Even there, the willingness of investors to believe that standard "this time it's different" line has been shown over and over again.
And, for some, having friends in the government to bail out the fools who bet on the bubble growing forever so you can get paid.
http://www.schneier.com/blog/archives/2009/11/fear_and_overr...
Or table here: http://www.schneier.com/essay-170.html
A free society is not exclusive of a strong government to protect property rights and handle externalities economically. It's when they take liberties with their charge when things get bad.
It would also make it economical for insurance companies to quite literally be thieves, and uneconomical for individuals not to pay protection money to the most powerful (and likely also most expensive) insurance company.