It’s a pretty normal concept that public transit is not a charitable program and must yield benefit commensurate with spend.

The benefits of public transit derive to all of society not necessarily those immediately riding it. That's true of a multitude of state spending, education, social services and so-forth.

The US doesn't directly charge for many of the costs of roads, certainly it doesn't charge for the drawback in the form of pollution and urban sprawl. But when you get to buses, suddenly "you're not a charitable problem..."

This argument has to face up to the fact that all of the best systems have high farebox recovery and all the American systems have low recovery except for NY (which is still lower than the good ones). Essentially, if it’s so great to have low farebox recovery why does the Tube, HK MTR, and Taipei MRT have high farebox recovery?

Theorycrafting is all well and good but if you claim that some metric X (farebox recovery) is negatively correlated with some outcome Y (frequent good transit) then you do have to explain why all the good outcome Ys actually have high X. Reality has to meet the theory.