Yet it works in China. The reason why it won't work is because flight is essentially subsidized - if you were to pay for all flight externalities, it would be way costlier than trains even on longer routes. Probably not on routes such as LA-NYC or tho.

You can travel 1176.3 miles via high speed rail (shinkansen) in Japan (Hokkaido to Kyushu).

3 of the air routes that cover this journey are in the top 11 busiest domestic routes in the world (#3 Sapporo to Tokyo-Haneda;#4 Fukuoka to Tokyo-Haneda;#11 Tokyo-Haneda to Osaka-Itami).

The highest ranking US domestic route is #30 (JFK-LAX), though by distance it's almost 3X (2827.2 miles).