I disagree. Once we have electric airplanes with lots of point to point connection, it will be both faster and cheaper. These should be coming on in the next 2 decades and that the minimum time it would take to build such a system.

Its a gigantic investment to do high-speed train and almost always is a burning money pit that needs to be constantly subsidies.

You already have an existing road network that with increasingly self driving EV (at least on highways) can be used.