Define "housing prices will collapse". What magnitude and duration of housing prices drop would qualify as "collapse"? If the prices are frozen for, a few years - it is not a collapse. If the prices drop by 10%, but then recover within these same few years - it is not quite a collapse either.
Home prices are down in the greater Boston area close to 12% in the last 9 months. The bubble is already here in "some" regions of the country.
I'd say considering how high prices have move the past couple years, prices would have to drop by at least 20% or more for it to be considered a collapse of any kind.
In addition, I have a very low mortgage on my home, especially compared to the current value, and they continue to build like crazy all around us... we have limited buildable land here which makes the prices of the raw land continue to climb and a great influx of people from other much more expensive areas who find this affordable.. lastly, the cost of building a home is getting more expensive by the day -- cost of wood, cement, etc., and post-Katrina I don't see that getting any better.