This model assumes constant housing stock, or at least, housing stock that grows slower than population. But this is not a given, so we need to ask, why is hous

This model assumes constant housing stock, or at least, housing stock that grows slower than population. But this is not a given, so we need to ask, why is housing stock growing slower than population? And no matter what the answer is, it tells us that the problem here is not population growth. More people means more hands that can build houses. Even if construction efficiency weren't gaining in terms of man hours, it would mean at least that housing could he built to keep up with population. There's no shortage of land, most land is uninhabited. So where's the bottleneck?