For those working in tier-1 and FANG like companies. Did you get in by being smarter than average or you just worked very hard (lots of leetcode etc.) for interviews prep?
Both should be an option.
Any result here will be heavily biased. People believe that they're smart, however most are simply better read. I'd be surprised that the distribution of "giftedness", if we could plot one from FAANG versus a large scale sample of people with the same economic condition/ background (based on purchasing power) will have any significant offset.
40/30/30 Luck/Work/Smarts
What if you’re hard working but have average intelligence?
So, you work your ass off. maybe, it takes 3 times as much for you to learn, but you still win.
Like with most things at this level, you ought to be both.
And luck