There are 100,000 high schools in the US.

The NBA drafts 60 new players per year.

Chance of being drafted in any year is 60/100000 = 0.06%. IOW once every 1666 years the best player in your high school team may be drafted.

If you're, say, top-10 in your state, then your chance is way better. Once every ~10 years a kid in top-10 might expect to be drafted (60/500).

What am I missing ?!