Banning international sales is a politically damaging move because it would crash the market value of existing housing, affecting those residents who own one (or more), particularly if they're on a mortgage. It also reduces the tax income from properties and propert sales. Banks probably wouldn't be too happy either that the security on the loans no longer cover the outstanding balance.
Things will probably shift when the proportion of renters significantly outnumber the home owners.
Things will probably shift when the proportion of renters significantly outnumber the home owners.