The market is being completely rational. What "overvalued" here means is "are homes expensive compared to local wages" not "are homes irrationally expensive." Normally this would drive construction but the market is distorted by credit such that new construction is less economical (a result of 2008.)
This also forms a feedback loop: people are giving up on labor since housing consumes more than they make, driving up the price of construction, driving up the price of housing. It's likely the dollar will crash before middle/lower class hosing will.