The lenders were every bit as 'irresponsible' as the homebuyers, so there's plenty of ignorance to go around. In fact, the burden for properly qualifying these buyers is and was on the lenders. But they were more interested in a fast buck than on long term solvency, and as a result, have to deal with massive foreclosures and defaulted loans.
So, the adults have to step in an make some rules. That's where government regulation comes from.
Calling gov't regulation "adult supervision" is a sad joke. It will not help. It will make it worse.
The lenders took risks and they have lost. Let them lose money. Borrowers took risk and they lost. Let them lose money too.
I don't see any need for gov't supervision or regulation. I don't see any problem at all. This is part of business and part of capitalism, that you have winners and losers. If you take away the losers then you will take away the winners as well. And do that, and you take away any incentive to work.