It originated as a marketing term for Skull and Bones, right?

Realistically, its a corporate buzzword that is supposed to mean that the game delivers an exceptionally high quality experience, graphically, narratively, gameplay wise...

...but what it seems to actually mean is that the budget and manhour count and development calendar time ballooned to far greater than the original plan/estimates due to incompetent management.

At this point, I propose that 'AAAA' applies to basically any extremely costly game backed by a huge publisher that owns many development studios, that has been in development for over 4 years before any kind of release, ie, stuck in development hell, execs convinced its going to be a massive hit such that they sunken cost fallacy other games or even other studios out of existence so they can keep funding their uber project.

With a definition like this, Skull and Bones qualifies, so does Concord and Suicide Squad.

Basically... it doesn't have to be from a grandiose marketing campaign attached to a AAA game, its more about being stuck in development hell and continuously funded to the point of destroying other parts of the business making it, like a financial cancer.