just a matter of time until a family owned empire runs out of even cadet branches and they have to dig back centuries to figure out who’s the monarch. The Germans got cut out forever.
I doubt that's how the German Hapsburgs saw it.
The normal procedure was for the son to inherit all his father's possessions. Which would have meant Charles V handing over his German lands as well as Spanish lands to Felipe.
However, in this case Charles' brother managed to abscond with half the loot. Half a loaf being a great deal better than none.
So it would be more accurate to say the Spanish branch was unfairly deprived of their German rights than the other way around.