One key thing to keep in mind is that, even if the population's stagnant, young people want to move out (and live in an apartment, later upgrading to a house wh

One key thing to keep in mind is that, even if the population's stagnant, young people want to move out (and live in an apartment, later upgrading to a house when they have kids) while their parents and grandparents want to age in place in their existing home (occupancy goes from say 3-4 to 2). This is why housing production actually has to outpace population growth just to keep prices stable.