I never understood why the Germans cannot get their shit together on commercial train travel. Austria manages to coordinate a wonderful federal train system across nine federal states without issues via the ÖBB, the Swiss also seem to have it down.
This is the fundamental mistake underpinning their train service since the long distance trains frequently have to wait for other trains to pass, cascading delays through the system.
That and an almost criminal level of underinvestment in the past 20 years or so.