Not long ago, I was having a discussion with some friends about real estate when the focus drifted to Cape Cod housing prices, which had plunged in the 2007-2008 real estate collapse. The consensus among the group was that prices would eventually rebound, and that patient owners and investors would come out OK. And that was no surprise. Most people tend to extrapolate the future from the past … and for most of our lives, real estate prices have gone up. Then up piped my brother-in-law the geologist, commenting, “10,000 years ago Cape Cod wasn’t there … and in...