I think there is a part of the book that was missed by the author of the article.

Gladwell wasn't trying to say that everyone could become an expect by putting in 10,000 hours, but rather he could explain the "Outliers" in our society because of the intense amount of work (hours) and favorable situations. Bill Gates enjoyed coding yes, but he had an opportunity to code much earlier than others. You look at Gates, Steve Jobs, and Bill Joy, all born in the mid 1950's with the opportunity to capatailze on a new industry. All with their 10,000 hours when they became of age and enough entrepreneurship take advantage of the newly developed market (or in some ways create the market).