[inferiorhuman]

It's also not reasonable to assume the resources exist for infrastructure like the largest cities.

Cities have actively made decisions to design cities around the car at the expense of every other mode of traffic. It's pretty unreasonable to expect that the status quo can't change.

In fact if you look at the Bay Area, the problems with transit are largely due to other sorts of dysfunction, not due to lack of funding. Los Angeles, OTOH, has been building out public transit in a coordinated way (far more successfully than the Bay Area has). IOW where there's a will there's a way.