It's well understood by the locals that the Hong Kong (and possibly other Asian cities) system reaps most of it's revenue from land rights around/immediately above the stations. In

In Asia transit hubs are often also retail hubs and the commercial rents become profit for the public transit system. This makes perfect sense as the retail value of the nearby land can most obviously be credited to the transit system.

I'd imagine that the problem with the United States is that this real estate was sold early on or was never owned by by the transit system allowing the spillover benefits of transit hubs to be captured by private interests.