Regulations??? The Free Market already holds the seller accountable. How can you not know that?
Government manipulation was involved in the entire process. Right down to bailouts. The Free Market doesn't make those loans and the Free Market doesn't bailout inept companies.
And who says banks should keep lending just to lend? You lend to qualified people in order to make money. The "free money" which was done through government manipulation of the housing market specifically the lowering of interest rates, which caused mal investment, which caused this depression. Same thing that caused the great depression, same thing we see now on the education cost bubble.