Your factual statements are wrong. The US population isn't flat over time, and housing (supply) decays over time. Prices aren't up everywhere, just the places people actually want to live.
Your figure doesn't contradict my claim. We have spare housing capacity in undesirable places people don't want to live (rural towns, small midwest cities). We have shortages in the (especially coastal) cities, where the jobs are. This is obvious from prices, which are set by supply and demand.
The only answer is that the increased observed demand is a result of the increased investment demand (rather than native demand)