Because space in desirable areas is finite? Because the creation of that proximate supply does reduce the desirability of those areas, not merely in terms of the upper class but the middle and--eventually, given a far enough point on the curve--the lower classes too? Because ruining things for everyone because of the investor class is antithetical to a humane society?

(Which is to say that there is absolutely an argument for increased supply, but rather that the interests of the REIT-helming class are not congruent with the interests of the people who live there, and thus can either come congruent or be ignored.)

Because we let people tell their neighbors they can’t build more housing, an action that used to be unconstitutional. Now it is, based on one openly racist court case from a hundred years ago.

Because theres not enough land and investors have more money than you. As an investment the average american will always be priced out.

Its priced to hit your maximum threshold on monthly wages expendable to rent with minimal savings.

Most cities have plenty of land but it is zoned exlusively for low density single family houses.