You think that land would be inhabited if it had commuter trains? You think the large cities which require a dense population for tax collection and often act as the hub for these transportation networks, perhaps have an incentive to fight nationalization and expansion of publicly held lands into housing developments?
Roosevelt set aside hundred of millions of acres of land not for eternal preservation, but for future development by generations that would otherwise not had land considering the industrial barons of his time would have completely demolished it.
>You think that land would be inhabited if it had commuter trains?
Yes, considering the distributed nature of the US's population pre-dates the car. Go look at a population density map from 1900. Tons of primarily agricultural small towns spread out over an enormous area. Back then most small-ish towns in the middle of nowhere probably did actually have commercial rail because there were no other options. It's just that when the other options did appear, rail went into terminal decline because it was simply a terrible way of serving those kinds of areas when cars and trucks exist. Even today when the spread is less driven by agriculture, people still prefer lower density housing because being stuck in an apartment building sharing walls with god knows who else stops being fun really quick. People like having a bit of space of their own.This results in lower population densities as a result of people's preferences about how they would like to live. Rail is a good means of transporting high volumes from one node to another. It is good at that and it should be used in that context. It is not good if you try to shoehorn it in as a replacement for all other means of transportation as some groups seem to be inclined to do.
Roosevelt set aside hundred of millions of acres of land not for eternal preservation, but for future development by generations that would otherwise not had land considering the industrial barons of his time would have completely demolished it.