The term AAA implies a sort of rating of quality, which is why it seems duplicitous to me.
It's a bit like the term "blockbuster" in film. Originally it meant a movie so good, lines to see it would go around the block. These days what it actually means is a huge-budget film filled with CG and spectacle, and studios labor under the belief that throwing that much money at a production will lead to blockbuster-scale ticket sales. Then they wonder why their "blockbusters" flop catastrophically at the actual box office.
It only implies a rating of quality because a large budget tends to imply high quality.
To give an example, no one calls Pillars of Eternity a AAA game despite it being raved over by gamers. The reason is simple. It didn't have an overly large budget, it had just a single artist.
People expect high quality to come from a big budget and that's completely reasonable (not duplicitous in any way). But the term still means a large budget. No one with much familiarity with the industry would argue otherwise.
I think the misunderstanding comes about from those who don't pay too much attention to the gaming industry as a whole misunderstanding the meaning because they guess at it via context and get it wrong. There is absolutely an implication of quality, but it is not a part of the definition of the term.
It's a bit like the term "blockbuster" in film. Originally it meant a movie so good, lines to see it would go around the block. These days what it actually means is a huge-budget film filled with CG and spectacle, and studios labor under the belief that throwing that much money at a production will lead to blockbuster-scale ticket sales. Then they wonder why their "blockbusters" flop catastrophically at the actual box office.