The solution lies in eliminating the entire concept of investment properties, and to classify single-homes as purely places to live. You do realize that part of "not enough" houses is due to corporate entities / investment vehicles / investors owning many properties.

And the types of cities (dense, highly-desirable urban cities like SF, London, Paris) where the NIMBY people complain most often also happen to be the most common markets for these investors to purchase/own multiple homes.