Releasing a perfect game that doesn't have any bugs isn't what the article is about.
It's talking about teams that have honed their craft over many years of developing titles they cared about working on and investing in continuous improvements, of which both Arrowhead and Larian have done.
I hate all acronyms that aren't defined.
You see it constantly in gaming communities. Ah, yes, the game "AC." You know the one.
Assassin's Creed? Animal Crossing? Armored Core? Ace Combat?