Housing affordability crisis — federal problem or local problem?

Housing has become the defining affordability issue for middle-income Americans in major metros. Median home prices in coastal cities now require incomes most residents don't have. The problem is real and worsening. The debate about solution is sharp: local zoning is the immediate constraint — single-family zoning, parking minimums, height limits, and permitting delays artificially restrict supply. These are LOCAL decisions. But the people making those decisions are homeowners whose asset values depend on scarcity. On the other hand, federal monetary policy drives mortgage rates. Federal student loans inflate tuition, which inflates parental wealth, which inflates down payments. Tax policy through the mortgage interest deduction subsidizes existing homeowners. Federal immigration policy affects demand. So: is housing affordability primarily a local regulatory problem (fix the zoning), a fiscal/monetary problem (fix the macro environment), or a tax policy problem (fix the incentives)? And who's actually positioned to fix it?