He isn't a good singer. That's not to say I don't love his singing. He isn't a dazzling guitarist, or more than a decent harmonica player. What makes him good isn't that he's competent - though I don't doubt that he is. It's his ability to innovate musically and lyrically that makes his music so acclaimed and adored.
I've worked with and been friends with all sorts of artists, writers, programmers. I find that the ones I feel have the most potential aren't the ones who are necessarily the most competent. In fact, a lot of people who AREN'T competent have an edge because if they're there, it's because they're really passionate about what they're doing, not just because they CAN do it. A competent programmer can do what he's told and churn out okay ideas. It's the incompetent ones, though, that want to program because they've got IDEAS. And while they can't be trusted in the same way, they've got a much better chance of turning out something worth keeping.
Not saying the article doesn't do a terrible job of explaining itself, but I think that Seth is TRYING to get at a good idea.