Comment by petsfed

The scenario to address is people who are forced to move (via e.g. layoffs, company relocations, industry collapse, etc) who are also suddenly saddled with a mortgage far higher than they can realistically payback while still moving on to whatever opportunity necessitated the move in the first place.

The first order consequence of treating housing as an investment vehicle is high prices, sure, but the second order consequence is that you dramatically increase the stakes when individual people buy any house whatsoever.

I would much rather give checks to every homeowner whose home value falls than to force even a single laid-off autoworker or whatever into bankruptcy (good luck buying a home after that) if they elect to move somewhere else for a new job and can't sell their house for enough to pay off their mortgage. If the consequence of a government policy to build more housing is that more people become homeless, then its failing.