I think only very few people would argue for a fully connected continental network. But as you said, up and down the coast is a very good usecase for high speed rail and it’s a shame you don’t have any yet.
For what it’s worth, in terms of urban development some of the big cities do move forward. I think that’s often overlooked when mocking the US for its car dependency. (But it will take a long while until the dependency debt is paid off)