There's another factor in HSR speeds: track degradation and maintenance. If you run the trains faster, they cause more wear to the tracks and require more frequent maintenance, and also tolerances on the tracks need to be kept tighter. Germany already seems to have trouble doing maintenance on time, so running trains faster would make this worse.
Yes, the German rail services prefer to build huge new trains stations instead of better tracks. We're waiting for 120->160kmh for years now, always promised, always moved to the future.
And probably the tear is bigger on curvy lines which most lines in Germany are, compared to e.g. China.