Concrete scenario: Imagine a division where the team in first place changes almost every week, where a squad that looks dominant on Sunday gets blown out the next, and where injuries to a single starter flip the standings. That's not a ruler—that's a revolving door. That's the NFC East right now.
No sustained control: To "rule" a division, you need consistent wins, a clear identity, and separation from the pack. The other side may point to a recent hot streak, but a few weeks isn't rule—it's a blip.
Parity proves my point: When every team has glaring flaws and the "leader" is just the last one to lose, nobody rules. They just survive.