Why trains suck in America
youtube.com
youtube.com
It's not so much that cities are unwalkable (he shows maps of Boston and NYC, two of the rare cities that one doesn't actually need a car). It's that most travelers aren't going to the city proper, and are going to want an automobile at the destination. It would be lunacy to tie yourself to the train's schedule, only to then have to rent a car at your destination.
The use needs really good city rail. If you had that, intercity rail would be a non-brainer.
In Germany, the city of Jena has ~100k people. It has three intercity trains stations (one that has an ICE - high speed line), and .. I think three of four trams lines. That's for 100k people.
America is spread out, but that's hardly an excuse. The auto industry has a lot of blame in this.
Similarly, light rail is personally advantageous not because the trip itself is better than driving (likely it's not), but because it allows one to not be burdened with a car at their destination.