New York to LA would be a terrible high-speed rail route. Just way too far. But the US has many city pairs - SF and LA, LA and Vegas, Denver and Salt Lake, Chicago and Detroit, Pittsburgh and Philly, and so on - where high-speed rail could easily replace most flights if it were built.
Some of those routes sound nice, but they don't usually have enough daily traffic between them to warrant the massive infrastructure costs. LA to Vegas would rival the distance of the longest European high speed lines, but with many fewer stops between and a fraction of the passengers between. Outside of connector flights, I don't even know how many people even regularly travel between Chicago and Detroit.
Part of the advantage places like Japan and Europe have over the US is not just that they are dense, but that their population skews to one massive metropolitan center. So it's easy to design a hub model where traffic patterns are easy - in and out of one area. You see this in the success of regional commuter rail networks in the US.
(SF and LA is a great candidate though, and it's failure a highlight of how hard it is to build in the US)
> LA to Vegas would rival the distance of the longest European high speed lines, but with many fewer stops between and a fraction of the passengers between.
Many fewer stops: that's a good thing. A fraction of the passengers? No, that's absolutely false. Brightline estimates 50 million trips between LA and Vegas every year [1], which is more than, for example, the total number of tourists to Paris every year.
> their population skews to one massive metropolitan center
Japan, sure, being a long and skinny group of islands definitely helps. But is that actually true of Europe? Germany has a great high-speed rail network (current on-time performance issues aside) with a very pluricentric population.
So this puts it at pretty low ridership and much higher ticket prices than equivalent lines around the world. (I'm very supportive of the project! It's just worth being realistic about the economics here.
My understanding of Germany's high speed network is that it is pretty comparable to the Acela - high speed in certain corridors, reasonably affordable, and dense population along the corridors. Which is pretty realistic goal for parts of the US. But often we compare to France's network which really outperforms nearly every other country outside of Japan.
