Why would landlords hate such a system. They can trivially pass on any tax to renters and have the incentives to figure out the loopholes in the tax code. It’s already common for single unit corporations to own rental properties.

Instead of taxing based on who owns the land, tax how it’s used. That way more units will be built increasing supply.

But then you’ll run into the real problem, not landlords, regular home owners who largely have a revealed preference to live on giant plots of land, in big houses far from multi unit dwellings. They’ll continue to use restrictive zoning to limit supply and keep prices up.