Real income in trades is up; that doesn't mean it's great pay, just up. Real housing costs have greatly outpaced that. It's the crazy post-2000 low interest boom-bust cycle that's wrecking the housing trades as a functional job. Trades are hugely oversubscribed during the boom, and the busts are too long to maintain the labor force.

If we want to build housing, we'll need a stabilizing force for that. I don't see a way to make that happen outside of govt intervention.