It's self funding in places like Japan and Hong Kong, but these places also engage in value capture. Train services in these places are basically real estate companies with trains attached to them. They diversified by making train stations shopping malls.

In any case, cities can engage in value capture for public transportation. Just direct some of the property taxes collected directed to public transit. Even better would be some sort of LVT, ideally but not necessary 100% of the economic rent from land.

In any case, public transit should also engage in value capture on their own property. If they own a train station, they should consider building on top or adjacent to it spaces that they can then rent out to tenants. It's not only efficient but also serve the public and the local economy and making public transit more economical to run due to higher ridership.

NYC also has subway statios with intense commerce, e.g. the Columbus Circle, or some bits around Herald Square. As a regular user, I find this convenient.

Almost every smaller station shows ads on walls, too, and every train carriers ads inside.

I don't see why the subway specifically could not be self-sufficient, or even a profit center. Sadly, this is not so, because of very large expenses, not because of low revenue.

Japan uses employer subsidy to break even. It a below the line tax in the same way health insurance is in the US.

> They diversified by making train stations shopping malls.

Like airports in America. We should pursue a similar path for our rail stations and, frankly, ensure they are heading toward locations that are walkable and connected.