Unlike Ezra, Dean Baker doubts bolder housing policies could have done much good:

Suppose we had instantly written off all underwater mortgages, would that have kept construction going? That's hard to see, since the enormous oversupply of homes would still be there. Would that have sustained house prices? It's hard to see how or why, the problem is that the bubble had raised prices far above any level that could be justified by the fundamentals of the housing market.