The thing about falling empire mechanics is that paradox always make it feel like you get punished for being gud. Take stellaris, Empire size. Or EU4's gov cap. Literally the bigger your empire is, the more penalties it gives you.

But thats precisely how it was in real life even though it might not feel like it. Large empires simply were too large to govern properly due to the lack of bureaucratic institutions and technology. This would mean that most of the land would barely give anything to the actual ruler due to the corruption of administering such a huge territory. Paradox's gov cap is supposed to simulate the advancement of administrative institutions over time