re: Can high speed rail work in the United States?

Time to gate is only part of the story, outside of travel time the train experience is significantly easier.

I generally walk in the station 10-15 minutes before the train leaves, which is impossible to do when flying. Also never had to gate check a bag on the train.

And maybe the biggest advantage of the train, don't have wait for a flight attendant to tell me when I can get up to use the bathroom.

I know not all trains are equal, but Amtrak business class, Acela, and Brightline all are phenomenal travel experiences.