Concerns about global overpopulation are not usually about housing, but how much of the total energy in the system can be safely diverted to our uses. I think it is reasonable to be concerned when one species controls a large fraction of the energy in an ecosystem.
On average, moving one person from a small town in the midwest to SF reduces resource consumption, so from that point of view construction in SF should be encouraged. Tearing down abandoned houses in small midwestern towns and converting them to wildland should also be encouraged.
