High speed trains (300 km/h) can happen only between hubs because each added stop costs time and makes those train no high speed anymore. Plus congestion if every train could use the high speed tracks, unless we build four or more parallel tracks instead of the usual two.

I don't see much change from the current scheme of medium speed trains (150 km/h) connecting medium sized cities and high speed between major ones. And slow trains doing every single stop for small cities, if they even have a station.