First, recognize that people will buy at all times and all prices. In the last downturn, people still bought all the way down, maybe just not quite as many.
Second, let’s face it we don’t KNOW prices will be that much lower in 3-5 years. I thought prices were nutty at the end of 2004 and that’s when I sold (October 2004), I was truely convinced they would crash and burn badly in ’05. I was wrong, a full two years later now prices in my old area are about the same as they were when I sold. I have noticed activity has decreased and places sit for a much longer time, but they have still be moving at fairly high prices.