Taxes are a simpler and more effective though. Ideal solution is a land tax on comparable sales price of the estate less some portion of replacement cost of non-obsolete fixed capital improvements.
If there is a lot large enough for 10 houses worth millions in the middle of the city next to publicly maintained infrastructure, investors might be able to avoid the cap by rendering the units uninhabitable, removing toilets, etc.
Land and property taxes do not have to be flat taxes. They are easy to make distributive by adding an X% deduction on the first $Y in tax payments per resident per billing period that they resided in the same jurisdiction that the parcel is located.
State governments can reform property tax system by appointing state commissioners to chair a state board of equalization attended by local assessors to reappraise property values at the state level. When this was done in the Progressive Era, states found large areas of land held by railroad corporations and barons which were not being taxed at all and put them on the tax rolls.
The federal government can also introduce a national property tax by amending and reintroducing the direct tax collected under James Madison. Any increase in direct land or property tax burden can be offset by distributive offsets for permanent residents or cuts to regressive taxes such as sales taxes and payroll taxes.