> There’s really nothing to infer - it’s in the public record. Keeping black people out of white neighborhoods (towns even) has been policy for generations in America.

Sure. But you’ve done nothing to connect that to the issue being discussed here, which is the inability of Americans to build public transit efficiently.

> Including where you live. Real estate is devalued in Prince Georges County because its population is largely black. Why is it largely black? Because white flight.

It’s actually a particularly early and successful example of Black flight (where middle class Black people leave to city to head to the suburbs): https://en.wikipedia.org/wiki/Black_flight. It was majority Black until the turn of the century, became majority white, and then became majority Black until the 1990s. But it’s population has never decreased since the 1900 census.

Prince George’s County is an archetypal American suburb. McMansions, Target, Whole Foods, strip malls, etc., and no public transit. Because that’s just what Americans like, regardless of race.

> Public transportation in the US is inefficient because it is underutilized even where it exists (nyc notwithstanding).

No, American public transit is inefficient because it costs multiples of what it costs to build in other countries, especially in NYC: https://www.nytimes.com/2017/12/28/nyregion/new-york-subway-.... And operating costs for the NYC subway are about double that of the London Tube, a very similar system.

> Riding a bus carries stigma that is racial as well as economic and this leads to transportation systems that few use, reinforcing a notion that they are wasteful and inefficient.

That may be true for buses, but trains carry no such stigma. The median income of people on most DC metro lines is six figures. It’s been heavily used by professionals and government workers since its inception. Prior to COVID, it was packed to capacity. But it’s still enormously wasteful and inefficient.

That’s the basic problem with your theory. Maybe that’s a plausible explanation for why there is no public transit in say Atlanta. But there are several major cities where public transit is heavily used by higher income and shire people (New York, Chicago, and DC at least). And it’s vastly inefficient in those places too, compared to Europe. And it’s also vastly inefficient in cities that lack the “white flight” racial dynamic because they have very few Black people, like Seattle and Portland. Your theory just can’t hold up to the counter examples.

> The true metric for comparison is not what a public transportation system costs to build, but how many people per capita use it.

What transit costs to build is the key metric. If Danes can build a fully automated subway for $200 million per mile, and New Yorkers can build it fir $1 billion per mile—and these are actual numbers—then for the same cost the Danes can build five times as much subway. That has two effects. That means you can build transit that gets near to the housing of five times as many people. So the same cost is amortized over five times as many potential riders. But there is a compounding effect too. The more extensive network is more useful to each of those five times as many potential riders (more likely to go where they want to go)—making it more likely that each of the potential riders will become actual riders.