Isn't the Acela the big exception to that rule? And it just happens to run between the very two cities in the sentence I quoted, and still slower than air travel.
The USA has TONS of intercity rail that nobody knows or cares about. Here's some by name: Pacific Surfliner, Cascades, Brightline. And that doesn't count things like Metrolink and other commuter rail.
There are more and I don't know them because I don't live near them. Acela isn't the only one.
Surfliner is about 3.5 hrs from LA to San Diego; ain't nobody gonna fly that, but lots of people drive it.
Virtually no one is taking the train from Chicago to Seattle, even when the train is full, its to get on the train, go 4-5 stops and exit.