Pac-12 was 5-3 against SEC, Big 10, and Big 12.
Teams that struggled in the P12 somehow managed to beat counterparts in other conferences; CU, Stanford, Arizona.
Oregon lost on a last second throw in SEC country (a road game essentially) and Ok State, one of the Big 12’s best, gave up 36 points to one of the PAC 12’a worst - Oregon state.
I don’t see any dramatic inferiority there. I think you make too much of the pac cannibalism.