Eh, I really don’t think this is representative. I’m a self-taught iOS dev who has only ever been self-employed and I just got a $420k / job from a public company. And I’m smart, but not some unfathomable genius.

I think every engineer should at least do some mock interviews on data structures, algos, and system design (there are TONS) of free study resources and then do a round of interviews. You only need one yes.