I don't think train can compete with a long distance means of transportation that is
1- equally or less time consuming.
2- works very similarly across countries.
3- only needs infrastructure at the start and end stops instead of for the whole journey.
What we need is to figure out a way to use less polluting, carbon neutral or non-polluting fuel for airplanes, and less of it with more efficient designs.
Agree about the long distance being subjective. I live abroad and have a job so for me it's not an option to use 2 days of my holiday time just to travel back and forth for one visit home. So I definitely mind that it takes considerably longer.
Well 3000 km is about 2h30 by plane. A train that goes 180km/h without any stops will still take 17h. I agree all the check in and travel to the airport definitely sucks, and I'd rather board on a train any day. But even with that nuisance, a regular plane going a typical cruise speed of 900km/h will still leave trains in the dust for anything farther than say 2000 km and make it worth it.