Hopefully if planes become more expensive we'll see some investments in the train infrastructure. Going from Lisbon to Paris even without changes will probably still take a long time even with a bullet train but if I can schedule a trip by night and sleep reasonably comfortably I think I'd consider it over the plane.

Catching a train in the late afternoon in the center of Lisbon, working for a few hours, sleeping and waking up in the center of Paris sounds fairly pleasant to me. Of course at the moment that's effectively science fiction.