Boom cities were never the problem. The problem is commuting, which stems from a lack of housing.
Forcing everyone out of the cities creates a worse set of problems. It means more wasteful roads to nowhere and doubling down on our third-world transportation infrastructure. It means more clearing of wild land, one of the best resources the US has if you've done any traveling at all. It means more boom-bust bedroom communities and vacant strip malls. It means more culturally insulated communities and Trump-like politicians.