Building out acceptable public transit over America's vast <1,000 people/square mile suburbia is probably not economical. First you would need drastically higher densities to become socially acceptable and legal. Then you would need decades of building until most of a metro area's population actually lived at high enough densities. Then public transit that's actually competitive with the status quo for mobility could start to pencil out.

Even when the density is there, the social mission of public transit agencies is to be a lifeline for the very poor. Improving service for professional commuters is at the bottom of their priority list. I can't even argue with that: the middle class can drive as an alternative, without bus service the destitute are just stuck.

The solution I want is unlimited construction of skyscrapers and travel mostly by foot and elevator. But if there's one thing our democracy is great at, it's preventing high rises. For the densities we have, our choices are cars or simply having commutes eat further into our already scarce free time. (No, public transit is not free time, as any vaguely useful train is crush-loaded standing room only).