Is Quadruple A simply a marketing term? https://gamerant.com/ubisoft-ceo-skull-and-bones-70-price-quadruple-a-game/ This game was meant to be a stand alone version of the pirate elements of Assassins creed black flag and seemed to give the impression of very immersive and realistic naval combat (more Master and Commander…
No one actually uses it and everyone knows it's stupid, not that that will stop any studio from calling it that anyway. If AAAA starts being a thing, then studios will soon come with "this is a penta A game".