If you look at pictures of cities from the early 1900s, one of things you realize is that even small towns of only ~20k people managed to fairly reliably have a streetcar line or two in them. (Actually, a lot of these systems still exist, the streetcars have just been replaced with buses.)
What happened to most NA cities is that they fully embraced the car by tearing down the city to make room for parking lots; there's a few cities where every other block in the city center is a surface parking lot. Combine this with systematic underinvestment in public transit (because it's seen as for people who are too poor to own a car), and you can see how we ended up where we did.
The main obstacle to fixing this isn't really money, it's in getting people to accept public transit as something that could be a viable mode of transit for them. There are far too many people who think that public transit is inherently unsafe and that by riding it they are at extreme risk of getting shanked (which includes the current Secretary of Transportation).
I'll add that cities in the U.S. west, which did most of their growing after cars were invented, just don't have what it takes. At this point they're trying to find a way to squeeze bike lanes into roads that were never designed for them. They're trying to pay for public transit between metro centers that are 50 miles apart and separated by gulfs of nothingness. A hub system is much harder to support when the center is so far from the edges.
> A hub system is much harder to support when the center is so far from the edges.
Actually that makes it easier, particularly if it is really nothing between as you can built high speed routes that are faster than cars, and put hubs out on the edges where people are. the reality though is it is rarely nothing inbetween.
Most people are not going to the "hub", they are going to some other location and so you need an anywhere to anywhere system that doesn't require traveling to the central hub. Most transit systems assume you work downtown and wouldn't use transit for anything else so they optimize for getting to the hub making any other trip impossible instead of optimizing for closer trips but making getting to the hub annoying (I think this is the wrong compromise, but ...)
I see what you're saying and it exposes a gap in my logic. I think the reason _I_ see it as hard is because I live in one of those gaps, so service is relatively limited compared to places further east with more density. Buuut the whole point is that, even though there are 95k of us in my town, we're still expensive to service for a 50 mile ride to the hub.