That makes no sense. Experts aren't limited to being knowledgeable about one specific topic. It's possible to be an expert on one topic <i>and</i> "just good enough" in many other subjects.<p>(Compare Stephen Jay Gould, who was a leading evolutionary biologist and writer of popular science, with broad non-expert interests ranging from baseball and Gilbert and Sullivan operas to the size of chocolate bars, to Paul Dirac, who was a leading physicist with almost no interests outside of physics.)<p>"Steve Jobs is not a better marketer than any of the best marketers in the world."<p>Being an "expert" at something doesn't mean that one is the best in the world. Quoting Wikitionary, an expert is "a person with extensive knowledge or ability in a given subject." This is also why we use the term "top expert" to distinguish between someone who is an expert, and the best of those who are experts.<p>If Jobs is as competent at marketing as the best marketers in the world, that makes Jobs an expert marketer almost by definition.<p>"Barack Obama is not a better lawyer than, say, the Attorney General"<p>Obama was a constitutional law professor at the University of Chicago. I find it hard to believe that U. Chicago would hire non-experts as professors. While I also find it hard to believe that Loretta Lynch, the current Attorney General, would have been hired as a professor of constitutional law given her background. These are different skills.