>>58459142GF obviously understands that box legendaries are better than everything else. And they understand that sub-legendaries like the paradoxes and treasures are better than regular mons.
Rotating regulations don't acknowledge the inequality between Pokemon that are in the same category.
If you play randbats on Showdown and you roll up Delibird, Luvdisc, Pinchurchin, Sunflora, Kricketune, and Vespiquen, your chances of winning are still pretty decent because of the level scaling.
But since those are all non-legendaries, every official format treats them equally to other non-legendaries like Gholdengo, Dragonite, Ursaluna, Archaludon, Rillaboom, and Sneasler.
I think Gamefreak would implement a system where, in certain regulations, you're guaranteed one or two random restricteds.
I don't think Gamefreak would prevent you from getting a team of 6 shitmons against 6 meta staples.