AAA games originally meant games with massive budgets that innovated. They gave rise to story driven games with high quality gameplay elements . One of the first AAA games was final fantasy 7.

From wiki

One of the first video games to be produced at a blockbuster or AAA scale was Squaresoft’s Final Fantasy VII (1997),[4] which cost an estimated $40–45 million (inflation adjusted $73–82 million) to develop,[5][6] making it the most expensive video game ever produced up until then, with its unprecedented cinematic CGI production values, movie-like presentation, orchestral music, and innovative blend of gameplay with dynamic cinematic camerawork.[7] Its expensive advertisement campaign was also unprecedented for a video game,[8] with a combined production and marketing budget estimated to be $80–145 million (inflation adjusted $129–234 million as of 2020).[9][6] Its production budget record was later surpassed by Sega AM2’s Shenmue (1999), estimated to have cost $47–70 million (inflation adjusted $73–109 million as of 2020).[10]

As opposed to

At around the period of transition from seventh to eighth generation of consoles, the cost of AAA development was considered by some to be a threat to the stability of the industry.[16] Staffing and costs for eighth generation games increased; at Ubisoft, AAA game development involved 400 to 600 persons for open world games, split across multiple locations and countries.[17] The failure of a single game to meet production costs could lead to the failure of a studio – Radical Entertainment was closed by parent Activision despite selling an estimated one million units on console in a short period after release.[18][unreliable source][19][unreliable source] Triple-A games also began to lose uniqueness and novelty; a common trend were a range of “grey brown” first-person shooters that drew on the popularity of the Medal of Honor and Call of Duty series but did little to advance gameplay improvements.[20][21] Ubisoft game director Alex Hutchinson described the AAA franchise model as potentially harmful, stating he thought it led to either focus group-tested products aimed at maximizing profit, and/or a push towards ever higher graphics fidelity and impact at a cost of depth or gameplay.[22]

The limited risk-taking in the AAA arena and stagnation of new gameplay concepts led to the rise of indie games in the early 2010s, which were seen as more experimental. This also led to the creation of the “AA” market in the industry, larger studios that were not at the scale of AAA developers but had more experience, funding, and other factors to make them distinct from the smaller teams usually associated with indie studios.[21]

So like i said. AAA used to mean high quality but has lost that meaning as time has passed and game companies stopped taking risks.