Don't forget that demand and availability go hand in hand. I'm not sure what happened after WWII, but definitely in the 1970s, subsidies were yanked away from Amtrak (which had a different name then IIRC) and handed to highway building instead.

I would love to ride the train - have wanted to for decades. That's "demand" in my book. But I don't actually ride the train, so I'm not counted as statistical "demand." As I said, I don't ride the train because the trip would be three to four times as long as driving; still much more expensive when you count the sleeper car (lodging) rates for a trip that would involve zero or only one overnight in a car; involve sleep deprivation through late-night transfers even if I could sleep in a moving vehicle; and still involve six hours of driving.