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.