Bugs are not equivalently findable and different techniques surface different bugs. The direct comparison you're trying to draw here doesn't hold.
If Google gave open source projects $100,000 per year for a competent QA person, it would cost less than this "AI" money straw fire and produce better results. Maybe the QA person would also find the 5 "AI" detected bugs.
At any rate, Google didn't employ "AI" to find this vulnerability, and Google fuzzing probably wouldn't have outcompeted these researchers for this particular bug (totally different methods of bugfinding), so it's really hard to find a coherent point you'd be making about "fuzzers", "AI", and "Google" here.