If libertarian ideas are so bad and so unpopular, why do politicians running for office use them so frequently to sell themselves to the public?
I do not believe that Libertarians actually invented the idea of financial responsibility.
On one hand, there was too much deregulation in the trading of mortgages and their derivatives. Lenders were unconcerned that their mortgages would default, because they sold them in a month or two to someone else. Eventually really shaky mortgages were sold in bundles with the assurance that they were a seriously sound investment, when, in fact, they were anything but safe.
There was too much pressure on lenders to con everyone into financing their homes, and refinancing it time after time.