The genetic threshold is negligibly low. People who are only above average are just as capable (and indeed just as likely) to become outliers as those who are exceptionally above average genetically.

Obviously there are some things people just can't do. The point is that as long as you can do something and have the opportunity to train at it for about 10,000 hours, you too can be an outlier. For basketball, for example, about all that takes is height above 6'1". Six. Foot. One. The joke of our perception of success is that we attribute success to the individual's genetics or hardwork without giving any acknowledgment that the opportunity is usually utterly out of their hands (see: Michael Jordan, Bill Joy, Bill Gates, The Beatles, major Jewish law firms, etc)