One solution is to revitalize second- and third-tier urban centers. Places like Nashville (already hot), Tampa, Detroit, and Indianapolis. Perhaps even Lincoln, Nebraska, and Birmingham, Alabama. Not everyone can live in Manhattan itself but the density, services, and lifestyle millennials want can be recreated elsewhere where land costs are practically zero. An art scene, a food scene, some condo loft conversions and trendy commercial space; it's a sort of county-level cultural CRISPR process. Smart entrepreneurs are already hard at work on this but it's an effort in which I think Government could provide massively effective incentives to accelerate the outcome.