Any rich person who buy more houses than he can live will create this problem. And there is no incentive for the government to do anything, because the real estate price is their tax, at least for the local government.

Incentive at scale is the problem. Incentives must taper off to make real estate / property investment less inviting the more is owned, this opening it up to more people at the lower levels.

But then will start the games of complicated / opaque business ownership structures allowing for individuals to own lots of real estate through different channels to make it look like it's separate entities.

And there is zero motivation from most of the world's leadership to clean up business ownership structure transparency because so many of them are ... participants.