HSR definitely has a place in urban design, but the cost can't be justified, which has been explained ad-naseum. For air travel, all you need are two airports and if the route is no longer profitable, you just fly to a different airport. Aviation's big advantage is its flexibility.

To be honest, I don't think HSR will ever catch on in the US because there is too much competition to justify the immense buy-in required to build that level of infrastructure. The entire US infrastructure is designed around Eisenhower-era freeways, which solidified cars/trucks as the US' choice of transportation, probably until we get those people-moving tubes from Futurama. Our cities are built on a hollow, urban core/suburbia model that has made cars a necessity in the vast majority of the US' major cities, whereas Europe and Asia have designed cities in a way that cars are instead a luxury. If people aren't relying on public transit as their sole means, then there goes most of your demand for HSR and then it's just a near-peer competitor for air travel with an obscenely high sunk cost.

I think the Green New Deal created a lot of interest in HSR, but I think very few people have actually read it. Here's the source document; it's not long (https://www.congress.gov/116/bills/h...6hres109ih.pdf). I was a civil engineer before I became a pilot and I think their solutions are vastly impractical and written by people who don't know the first thing about construction. As a moderate, neutral party, it wasn't even a thinly veiled Trojan Horse for socialism to me (Just read page 11-14 in its entirety, it's double spaced with huge margins).

Don't get me wrong, I'm all for sustainability, I just don't think HSR is the answer for the US. But we already have a very cheap, functional system in place, so I think we'd be better off trying to improve what we already have. For example, if we could figure out energy storage, rooftop solar panels could power your house, charge your car, provide hot water, etc. Then we'd be 90% on our way to complete sustainability without really changing the American way. I'm not saying this is THE solution, I'm just using it as an example.