I've been a systems dev for a long time and have debugged many such tricky issues before. Even on teams of experts, this type of issue would take someone really capable weeks to track down, especially because the repro environment is hard to obtain. And the opportunity cost of doing this type of work for a rare bug is high, since you may never get to an answer and have burned a lot of time. So in practice I solved most of this type of issue early in my career before I had a family and before I had higher level work to do.

The ai doesn't have the same incentives as a human. It can also be applied to the repro where it exists.

Your mechanic analogy is a bit inapt. Sure they're experts and can replace your engine much better than you can. But tracking down a non obvious system level bug like this one is much less repeatable and much harder because the problem has already been filtered through a lot of reviews and testing. As a system becomes mature, the bugs become harder and harder individually to track down.