I think I was better than most kids at math, particularly algebra, but those kids grew up and caught up and I suspect many of them are as good or better at math than I am. I know nothing about child psychology or anything adjacent, but I honestly think a lot of "advanced child" stuff is just maturity.
My friend's child is profoundly gifted (160+ IQ). He is 12 years old and finishing Calculus and next year will be taking college math courses. His friends are a year younger than him and have qualified for AIME since they were 8 years old.
Giftedness is very real, and it's not just "maturity". Their brains are different. Seeing them squabble over math problems, it's like watching people talk a different language.
Anyway, if that’s the scale, it still can fit with the “doesn’t lead to exceptional outcomes”. I am a perfectly competent software person, and maybe I even understand some of the mathematics behind it better than the average programmer, but I am still basically just an “adequate” worker, and honestly I am afraid that I have more or less peaked career-wise. I am sure that some prodigies do great but the article seems to indicate that they’re rarely exceptional at adulthood.
[1] honestly I think that IQ is stupid and that it’s dumb to try and distill something as complicated and multi-faceted as intelligence to a single dimension or even a couple dimensions is pretty reductive.
I like to think I’m pretty clever, but I almost certainly would not have gotten 160 if I hadn’t gotten the practice test.