Not to shit on your perfectly reasonable parade, but in Germany there is high speed rail through the whole . takes about 6 hours from top to bottom.

Maybe not a great example there, with that running something like 100 km/h average speed.

If you bump those numbers up to be competitive with actually high-performing HSR operators, that trip would take 2-3 hours, immediately killing any competitive edge that air travel would have on those segments - 2-3 hours will basically get you to the airport and through security, you’ll have arrived already if you were on a well-performing train by then.

HSR is the best alternative for any trip up to approximately 800 km, at which point air travel starts beating it out. This is for daytime travel only - trains could be competitive for far longer distances with overnight sleeper service. I’d not be against taking night HSRs going between any points in Europe basically.

Alas, this would require non-shit politicians, which definitely does not exist