Nobody I know of is proposing only high-density housing. The issue, especially in places like the Bay area is that density should have been going up closer in,

Nobody I know of is proposing only high-density housing. The issue, especially in places like the Bay area is that density should have been going up closer in, instead of paving over the garlic fields in Gilroy. It is much less costly to make subway stations bigger and add cars to trains than it is to extend rail farther out. There are existing solutions that would "create systems of small cities that can satisfy the needs of the many as well as the few." If US trains did not suck, Lawrence, Worcester, Springfield and more would see an economic boom and take pressure off the Boston housing market. I can fly into Schiphol overnight and take a train to Hilversum in the morning more easily and vastly more reliably than I can take the MBTA to Amtrak to New York.