> Zoning is largely local though, so the actual political control of the thing that would make this situation unsustainable is held by incumbent owners.

Or a solution that speaks to that. E.g. A progressive tax like income is but in total residential property value.

Something like <$1m is 0%. $1-3m is 1%... Etc. Make the top rate untenable to own more than $Xm in residential like 10% + top rate for anything held under obscure ownership structure.... or whatever bands/percentages that seem right.

There is an increasing small group of people that own/inherit significant residential ownership. And while there is a physical constraint side of housing, fixing residential as investment vs place to live can take a heap of pressure off and is a much easier/faster point of solution I feel.

I cant remember where I heard but someone said residential property can either be good for investors or owner occupiers. Not both. Ultimately the government needs to prioritise occupiers in my view anyway as not just for happy people, but this brings stability and economic benefits to a society.

I would love to see a "land tax" instead of a "property tax" - so if you have a bungalow on land that would be very profitable as a tri-plex you get taxed on that potential vs. on what you happened to have on the land... but that's politically infeasible unfortunately.