Last time I went through LAX there were no good options for getting from there to downtown LA.
In Japan, I can literally show up for a Shinkansen five minutes before departure and hop right on.
Airports for short range traffic are fscking awful.
* I can’t just show up for the Acela five minutes before departure. It’s not nearly as bad as flying, but there is ceremony involved.
* Security and boarding are a lot better when you are a frequent business traveler. That’s who is going to make the bulk of the DC-NYC trips regardless of modality. We shouldn’t compare the tourist experience between the two.
Contrast that to the TGV in France, which zooms around at 200mph and covered one of my trips between Paris and Avignon (~430mi) in ~2.75hrs about a decade ago. US train infrastructure feels extremely behind in comparison. Perhaps it's because of a greater emphasis on highway travel.
That said, the NYC-Montreal and Boston-Toronto lines are lines that absolutely should be dedicated high-speed passenger rail in addition to the NEC, but they are not even dedicated passenger rail lines at the moment let alone proper 220mph HSR lines.
Roadbeds are maintained to freight train standards, e.g., the difference in height of the two rails.
Amtrak depends on the "host railroads" who are not very hospitable to passenger traffic.
So it seems pretty probable to me that Acela came about because there was already a huge and increasing demand for such a service.
To be honest, when it's my own money I usually just take the regular regional train. It's about half the price and because it can piggyback off the electrification done for Acela, it takes less than an hour more.
On other routes being slow is a massive liability though. If people could get from San Francisco to Portland in 10 hours, or even 12 hours, instead of 18 hours, it would be much more practical. At 18 hours it messes up your sleep schedule rather than just giving you more time to read.
It might just not be worth it to spend more on rail travel from Portland to SF though. It's just a reality of geography rather than somebody's mistake that travel from SF to Portland is harder than travel from DC to NYC.