Bingo.

Never seeing a good public transport project everyone assumes that it’s not possible. It is possible when the goal is to provide transportation services, not resource extraction from masses to limited (in the grand scheme of things) number of individuals.

How many years and how many billions do you think it would take Europe to build this railroad?

Yes. Isn't Ryanair more popular for the distance this California project would cover? (800 km)

Both options exist and both are heavily utilized. Having multiple options helps alleviate congestion issues.