Only you, and “No.” LOFL

Humans are variable in many facets, so naturally some of them will inevitably be below average. Some perhaps will will try to better themselves and succeed, but like the quote in the article observes many will lack the self awareness. I did see recently someone complaining about the frequency they are called stupid and were completely oblivious to the idea that they might actually be stupid. (not acquainted with Occam's razor and commenting on it seemed futile)

Yes and no in matching order.

This makes me think of dunning kruger.

Yes and yes. But if we start augmenting our brains with more and better neurons and biocircuiting, what do we become? What are our objectives? More memory storage or information access? Can we reprogram the brain's development to be more like identified geniuses?

The ignorant can learn. Those born stupid will remain stupid until the day they die. I'm not convinced critical thought can be taught.

There is a difference between not being highly intelligent and refusing to use whatever intelligence you happen to have, howsoever limited, to your own benefit and to the benefit of those who are around you.

It is those who simply refuse to engage in critical thinking of any sort that annoy the crap out of me.