> most people don't want to use
I'm not sure if this was intended or not, but this is a common NIMBY refrain. The argument of "This thing being advocated for that I'm fighting against isn't something people want anyway". And like walkable neighborhood architecture, extremely few Americans have access to light rail. Let alone light rail that doesn't have to yield to car traffic.
Regardless, the cost arguments fall apart once you take the total cost society pays for each system instead of only what the government pays. Because when you get the sum of road construction & maintenance, car acquisition, car maintenance, insurance, and parking, it dwarfs the cost of the local transit system. Break it down on a per-consumer basis and it gets even uglier. New York City is a good example to dive into, especially since it's the typical punching bag for "out-of-control" budgets.
Quick napkin math pins the annual MTA cost at $32-$33 billion and the total cost of the car system between $25 and $44 billion per year. Since the former serves somewhere around 5.5 million riders, and the latter only about 2 million, the MTA costs $5,300-6,600 per user annually where the car system costs $12,000–$22,500 per user annually.