[trident5000]

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.

[bullfightonmars]

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

[nitrogen]

Because theres not enough land

There actually is enough land if you look outward from major cities, but billionaire investors already own that, too.