Yah, they select against self-awareness. I think the dirty truth is that thinking you're the best in the world is more important to these companies than actually being good. If you have an outsized self-perception, you'll put up with unreasonable deadlines and terrible conditions on account of pride. That's attractive to someone who's in the business of exploiting naivete.

I'm a mediocre (96-97th percentile) software engineer whose expertise pertains more to the software ecosystem and economy. Knowing it (and myself) as well as I do, I know I'm not the best in the world. I even have that rare trait of knowing what I'm missing, and there's quite a lot in that category. But I'm more than good enough for 99.8% of the tasks that people need done, given reasonable learning time.