I saw an interview with an all-time great NBA basketball player. He was a top high school player and described his childhood like this: When you were at the movies, I was practicing. When you were on dates or hanging out with your buddies, I was practicing. When my family went on a cruise, I was dribbling up and down the hallways. ...

Now imagine the prodigy athlete who goes the movies, hangs out, and relaxes on the cruise. How could they hope to compete?

I recently read an interview Jadeveon Clowney, who was the country's top high school American football player and then the number one pick in the NFL draft. He was widely called a 'freak' athlete. Clowney said he didn't really learn how to understand and play the game until the NFL; until then he could dominate with his physical ability, even playing against elite college players.

He's played 11 years so far in the NFL, which is a long career in an extremely competitive job. We can call him truly 'good'; he was chosen for the Pro Bowl three times, in those years making him > ~85th percentile for his position, but nobody thinks he's an all-time great.

There's not such a clear story about where these people come from. Maybe the basketball player just wasn't as athletic (relative to the population of elite athletes) as Clowney and had to make up for it. Maybe Clowney would have been an all-time great with more work. Maybe there are many other inputs besides work and talent.