The tendency of people and organizations is to lose focus. So one way to identify outstanding people is by their ability to commit and focus on something for a long period of time.
The only people you should hire are focused ones. The only competitors you should worry about are the focused ones.
I have a suspicion that most adults (75%+) could pick any skill—excluding sports—and work their way into the top 10% in the world simply by working exclusively on it every day for two years.
But almost nobody displays that degree of focus, so we will never know.