[dasht]

Bah. I call BS. You sound like a San Francisco real estate speculator or developer. "High density infill" projects are loved by the people who make money off the development of the property but no matter how much you weaken zoning protections to get there they somehow never manage to swing prices when demand, like it is now, is just so much greater. What you do accomplish with these projects, typically, is building very high-end price units, often of compromised quality (cheap materials, absurd square footage, etc.) Of course this does have the effect of reducing gentrification. On the contrary it steps up the pace while simultaneously leaving the city with a less desirable housing stock in the long run.

[tptacek]

I call "math". Manhattan is 34 square miles and houses 1.6MM people. San Francisco is 49 square miles --- 1.5x bigger! --- and houses just 810k.

Working class people in SF aren't just upset that they're losing apartments they've lived in for years; they're upset that they can't predict where they're going to have to move to and where their kids are going to school; the whole city is crunched.

[scythe]

>but no matter how much you weaken zoning protections to get there they somehow never manage to swing prices when demand, like it is now, is just so much greater.

It doesn't make sense that they would, but that's okay because it's not the goal. In oversimplified microeconomic terms, new housing is built for the current price point, and can have the effect of preventing a price rise -- preventing demand from exceeding supply. Prices come down when supply overgrows demand, which doesn't happen by increasing supply, because the people doing so would lose money: demand has to decrease. tl;dr: high prices cause construction, but it's a negative feedback loop.

Concerns about housing quality seem misplaced. In a large majority of cases, new housing tends to be better than old housing, thanks to innovations in construction. High rises were popular in the '70s, which is why low-quality high rises are common: they're old.