Our keystone national housing policy focuses on appreciating prices.

A sensible national housing policy would focus on improving the characteristics of the housing stock (improving energy efficiency, removing lead, etc). Of course the building code moves forward over time and new housing generally beats older housing on metrics like that, and there are occasionally tax incentives for making improvements. but none of that comes close to the mortgage interest deduction in scope.

It would also focus on affordability. It's clear enough that with 40 or 50 years for the policy to work and ~1/2 of the nation not having much of any wealth that home equity is not the path to universal prosperity.