That is true, but unfortunately not everyone can decide when they move. Losing a job, having a family member get sick, etc can force a sale and realization of loses.

But overall, housing prices do increase over time relatively inline with inflation. So even if Vancouver takes a huge hit in the short-term, over the long haul it will keep going up.

One interesting thing I noticed is that some housing markets don't really go down that much, they just stop growing. I can remember the home my parents owned in Toronto. They sold it for $325K in 1990. In 2005 I looked up the price and it was about the same. Adjusted for inflation, the it was a price decrease.