It's far more reasonable to change this to a challenge to become a scratch golfer or something similar. I don't think Gladwell meant that anyone could become one of the best in the world at anything with 10,000 hours of work. Such a statement is somewhat insulting to those that have devoted their life to their craft. Instead, that with 10,000 hours you could become very good at anything. Enough so that you could be considered very skilled/knowledgable in that craft/field.