I'm confused as to why the US seems to fail or fall so far behind in infrastructure compared to other developed nations. It seems that we throw money at our problems but seemingly get nowhere. It's sad because there's many amazing things about this country, but we cannot do basic things like make trains run on time.
I'm throwing darts at the wall here, but I think part of the problem is our sprawl and geographic size/car culture. In the typical US city you have the wealthier suburbanites living in separate towns/counties than the city they work in. This segregates the local funding because no one wants to pay for someone else's projects. And state funding doesn't benefit you as directly (e.g. state highway projects) and probably…
The personal car took over America for a reason: it's the fastest and most pleasant way to get around. Cities only start to seriously entertain public transit when they hit car culture's scaling limits. New York passed those long ago, so the more interesting question is why they can't maintain what they already have. Unlike a typical American city, Manhattan is richer and more expensive than its outlying bedroom communities, and transit access is a premium feature of luxury real estate rather than a handout to the destitute. I don't think your explanation works in this case.