I'm pretty sure we've had a collapse in trade hours available per capita at a rate that's far exceeded productivity gains. If a GC has a fixed labor pool that can build at either 200$/ft or 600$/ft, then labor constraints basically makes the housing market an open auction. Housing costs have gone up because you're bidding on the final cost overhead per foot. The result is the trades aren't paid more: just the house does. (Nicer finishes, etc.)