> when I come to the USA I try and take trains when I can. Yesterday I took the Amtrak from LA to San Diego...
If you've mostly taken trains in the US on the coasts, or for long cross-country trips, you may have an overly rosy view of the situation here.
I live in a mid-sized US city, the capitol of its state, with a metropolitan area population of around one million (city A). To reach the nearest city of at least this size (city B) by car is only a two hour (<150 miles) straight drive along the interstate. Both these cities have train stations serviced by Amtrak.
The only itinerary Amtrak offers to get from A to B using their service passes through city C, which is more than 500 miles from city A or city B. It's a 30 hour trip.