The challenge for mass transit systems in the United States is that if the operating costs are so high that it requires heavy subsidization from taxes it becomes a very tough sell politically. "Our taxes are being raised by how much to subsidize the subway???"
Perhaps that's just a failing of how mass transit systems are sold to the public though. If your mass transit system takes several hundred thousand people off the road every day and significantly reduces gridlock it makes everyone's commute better and wastes a lot less time and gas. Maybe that's how these systems need to be sold rather than, "It'll run profitably after X years."
They also promote economic activity (people can get to work and spend less time commuting). Even cities in red states are striving for more of that (though to be fare, even those cities are mostly blue).
Perhaps that's just a failing of how mass transit systems are sold to the public though. If your mass transit system takes several hundred thousand people off the road every day and significantly reduces gridlock it makes everyone's commute better and wastes a lot less time and gas. Maybe that's how these systems need to be sold rather than, "It'll run profitably after X years."