> it’s also granite on swamp, with significant cost multipliers to get anything built

We're still talking about busses, right?

If we're pivoting to subways, the granite isn't why building subways in New York is expensive. It's one part the existing density of the city and nine parts the usual American permitting hell [1].

> I’d love to see some data on why modern city states are the only ones able to build public transit

Fixed costs scale with distance (not area--routes are 1D) serviced. Revenue potential scales with area around stops. (And drops non-linearly as travel time for potential customers increases from each stop.) Latency and travel time scale inversely with number of stops.

Put it together and you need revenue per stop to cover the cost of, ideally, the distance halfway to the next stops. Herego, density reigns supreme [2].

> you’re a NYer and saying pub transit is untenably uncomfortable

I said busses are uncomfortable. Trains are fine. But you're not going to get an LIRR and subway system working sustainably in Dallas, Baltimore or even Chicago--everyone already owns a car, which makes the marginal cost of driving oneself uncompetitive with public transit.

[1] https://www.nytimes.com/2017/12/28/nyregion/new-york-subway-...

[2] https://www.sciencedirect.com/science/article/pii/S259019822...