NYC's subway system is an amalgamation of three systems, two of them built privately (but both of whom subsequently went bankrupt) and the third built by the city.
Of course they went bankrupt. We built free to use roads to compete with them.
They went bankrupt in part because although privately owned, they depended on a city charter to operate, and the City used that charter to force them to keep fares unsustainably low (I believe it was a nickel).
Same as Seattle! And thank god Japan and Hong Kong don't do that to theirs.