Debating San Francisco's housing crisis

I don't often find Tim Redmond's blog helpful in understanding local issues, but his latest (Why market-rate housing makes the crisis worse) at least raises the relevant questions. Reading the take-no-prisoners comments is also essential:

Peter Cohen and Fernando Marti at the Council of Community Housing Organizations have dropped a bombshell on the standard City Hall analysis of affordable housing. In an op-ed in Sunday’s Examiner, the two explain how market-rate housing construction is NOT the main source of financing for affordable housing.

In fact, they note, the money that market-rate developers pay to subsidize affordable units doesn’t even cover the housing impacts that their projects create.

Let me say that again, because it’s critical (and not easily understood, and should have a profound impact on policies like the Mission Moratorium): If you require less than about 40 percent affordable housing, the net impact of high-end construction is to make the housing market worse.

How is that possible? How could building more housing (at any level) be a net problem for the housing market? Doesn’t more housing trickle down and make things better for everyone?...

See also this and this from Planetizen.