If it's not profitable, it's not considered worth doing in the US. Public transportation does not pay for itself, even in high volume (relatively speaking) area

If it's not profitable, it's not considered worth doing in the US. Public transportation does not pay for itself, even in high volume (relatively speaking) areas like the Northeast Corridor, so it's always in danger of losing federal funding. Also, it's a localized issue. Nobody wants to spend money on transportation until the population density in the area grows to the point where things will break down unless its there.