Development and transport are systems that achieve critical mass and then cannot easily be changed. One hundred years ago U.S. cities and towns had extensive streetcar systems and were connected to each other by electrified rail. The current U.S. system of autos and sprawl was forced upon us.
This system is economically and environmentally unsustainable, and is propped up by USD trillions in subsidy and ignored externalities.
Superimposing rail solutions on top of autosprawl will not work. Instead, we must dismantle the system gradually by turning to buses, then streetcars, then bicycles and walking.