I don't think people know how much QA time is necessary for a project as large as a game...Yeah it would not be used during all of QA. That wouldn't even make sense considering a lot of QA isn't playtesting and happens during development.
Plus do you want the amount of glitches that pop up early development to get put into the A.I.?
They'd have to do it once QA is finished.
We're only talking about the very last qa moments.