Realize here, for the most part, I'm giving you a Readers' Digest version of a book I just read, though I can certainly see the merits myself.

sole, I would have agreed with you completely not terribly long ago. However, that's because you are looking at success of these outliers (durr, book title!) through the lens of individual merit. You think there must be an individual reason for the success of (for simplicity) Michael Jordan. The most obvious source, then, would be genetics because we know that his genetics are guaranteed to vary from everyone else's. You look at the surface and see a guy who's 6'6" and assume that has something to do with it. The truth is that there are more people who are 6'6" and not playing basketball than there are people who are. What Michael Jordan's genes did was cross a (relatively short) threshold. In the NBA, that's about 6'1".

Likewise, his hand-eye coordination was good enough to get noticed at a young age. His natural athleticism made him good enough to get picked on the playground. His parents were middle class, so he could afford to use his time playing pick-up sports, playing on travel teams, etc, rather than working an 8 hour shift to make ends meet after school. His birthday is early in the year (February) which meant he was at the leading edge of the cut-off date for recreational leagues (January 1.) He was always older than the other kids, meaning as a child he was naturally more physically matured. This gets him noticed by coaches, which give him extra practice. His skill starts to separate him on the playground (he's the best on the court, so he gets the ball more... gaining him more practice that the worst guy on the court who rarely gets the ball.)

By the time Jordan was in high school, he was playing 3 sports (baseball, football, basketball.) Though he was obviously a competent athlete, he didn't make Varsity basketball his sophomore year because he was (you guessed it): TOO SHORT. He grew from 5'10" sophomore year to 6'2" his junior year, crossing the threshold, after which he became a star (he already had plenty of time devoted to basketball and general athletics; the skills were refined by that point.) He then went on to play for UNC and the NBA, where he was always a standout player (the best player on the court continues to get the ball most, remember?)

This is also a perfect example because Jordan did what most athletes do not: he switched sports mid-career. Remember, all of Jordan's time was dedicated to Basketball after high school (and, because baseball is more difficult to play casually or train for than basketball, likely his whole life.) What happened? Jordan was fine athletically, but lacked the skill for baseball that he had developed through hours (10,000 hours, to be exact) of training for basketball. He had the same set of DNA, but was only able to succeed at basketball, because basketball is what he was pushed into playing.

There's a similar story behind the success of Bill Joy (Sun Microsystems), Bill Gates (Microsoft), The Beatles, and many of the major Jewish law firms in New York. Your genetics get you to a threshold, and only 10,000 hours of training can make you a success. The only thing all of the outlier have in common, for the record, is a willingness to work hard honing their respective crafts.

The smartest men on earth aren't the most successful, but the smartest men on earth are all in the top 20%.