I don't agree with it. There are many capital cities that are in terrible locations for highspeed rail and are would be a diservice to the rest of the country.
Cities like Amsterdam, Berlin, and Viena are just the worst places to reach for most of their respective countries. Say you live in Munich and you want to travel to Amsterdam, you are still stuck on the slow train if you focus on a Berlin-Amsterdam route.
If high speed rail is supposed to be successful it should be about covering geographical distance fast. Or the car and planes are still going to be the prefered option.