One other thing to keep in mind is that there was a great boom in building in the US during the 1970s and 1980s, and many of the homes built during that period

One other thing to keep in mind is that there was a great boom in building in the US during the 1970s and 1980s, and many of the homes built during that period were built using substandard building materials and techniques, many of which are no longer up to code for new construction but were grandfathered in. How many of those millions of homes are actually solid, reliable structures? How many suffer from moisture damage, mold, or have been poorly maintained? What kind of cement was used to pour the foundation? What kind of insulation? How many insect or rodent infestations has the house suffered? There is a vast difference in quality between an old building in a city that has been renovated for apartments compared to a suburban home that has essentially gone unmaintained for decades and was built as part of a speculative housing development project by someone who had no long term interest in the quality of the construction. I think we'll start to see a gradual crumbling/disintegration of suburbia as the houses fall into disrepair and the mortgage debtors are in too far over their heads to afford proper maintenance. The right thing to do in 2008 would have been to let the prices fall and stay down, to encourage proper renovation and maintenance.