I'm also not so sure that it will go far in terms of easing housing costs. I just moved to the SF bay area from Boston and live outside of SF, but close to a CalTrain stop. Everything is walkable for me, but the cost of living is comparable to SF (albeit the apartment is a bit larger).

I have friends in the suburbs of Boston who have to commute into Boston for work, which is not something I have to do, as my community is a bit self enclosed. But their housing situation is not necessarily much better than mine was in Boston. Yeah, double the square footage for the same price but there wasn't more reasonably priced housing available that close to the commuter rail, and there wasn't exactly much to do in those areas outside of grocery shopping and commuting.

Anyway, I'm starting to ramble a bit, but I'm failing to understand how more housing stock will improve any housing crisis. At best, it will keep the prices from inflating at the current rate further, but I don't see an increase in stock actually lowering prices. Developers are just going to build for the same price point as the market has now.