@Alon applies induced demand to European rail travel here:
"It would offer reasonable service to other places in Southern Europe with warm climate. Speeding up the Paris-Nice TGV means Parisians would choose to travel to Nice more and to islands less. Building high-speed rail approaches connecting to the base tunnels across the Alps means Germans, especially Southern Germans, could just go to large Italian cities instead of flying to islands or to Turkey."
https://pedestrianobservations.com/2024/12/30/quick-note-high-speed-rail-and-decarbonization/