Some of those young people cultivate skill by getting practice during youth. Doing that while young builds a compounding machine of personal interest + confidence + progress.
I have never seen broad data to support this, so discussions revolve around anecdotes[1]. That's fine by me though because we have countless examples of the legends of their craft who fit that mold: bill gates, zuck, warren buffett, taylor swift, mozart, da vinci... the list is long.
No single system will work for every single student. But that isn't the point. The point is that the best of the best deserve to feed their interests at a young age, which the current US upbringing limits. How many more bill gates and zuck-level creators could the world have if more talented youths could cultivate their talents very early in life?
[1] Although not broad data, the thinking behind these works build on a similar point: Thiel Fellowship [https://thielfellowship.org/]; PG's essay How to Do Great Work [https://paulgraham.com/greatwork.html]