"Looking forward rather than backward, nothing in Germany’s urban geography is an obstacle to a connected high-speed rail network. With central stations and less of the population living in truly isolated rural and small-city communities, Germany can expect to greatly surpass any other Western intercity rail network if it builds high-speed rail, more than reaching DB’s pre-corona 250 million ridership target."
Given a certain proportion of journeys that you want to cover with high-speed rail, I'd say polycentricity still means you need to build more infrastructure than under a monocentric (France) or linear (Italy, Japan) model.
Maybe we need an ICE-Express (I know what ICE stands for). An ICE shouldn't have to stop in every city, that's what ICs and and regional rail is for. It gets ridiculous on lines through the Rhine-Ruhr area, all very large cities that on their own merit an ICE stop, but they're spaced five minutes apart. There is definitely a need for real high speed rail, Hamburg to Munich in less than 3h should be possible, it takes around 6-7h now.
Yeah, if I'm not mistaken a lot of the tracks for the french TGV and also the japanese Shinkansen (literally means new main line) are separated from the tracks for slower trains like cargo and regional. But whenever I see the protests of people when there are plans for new tracks I start doubting that I'll ever see a fully separated high speed rail network.
It is slow because it shares the track with other trains. The point of high speed rail network is to connect big hub together without removing existing network. The stop would be every 150/200km.
Imagine a Munich Berlin in 2h, that would kill any flights between the two cities.
It makes no sense for ICE to stop in every small town. The entire point of express service is to prioritize speed over coverage. And that entails building enough rail capacity to avoid being throttled by slower lines.
Frances population is far more centered in mayor hubs while in Germany the population is dispersed much more homogeneous.
In some places the ICE stops every 20km, there are too many curves, or it shares its rails with slower trains.
There is no need for high speed rails here because you can not accelerate anyway.