You could rephrase the whole article, "Just do anything enough to get good at it. It doesn't matter what you want or like." My response: "yes, it really does."
My response to your response: "no, it doesn't." You have to progress beyond the initial period of total incompetence, where nothing is fun. Your guitar strings buzz mutely, you keep dropping your hand and your opponent punches you in the face, and javac keeps yelling at you about "array index out of bounds." After that, though, the increasing success in the activity becomes a positive feedback loop, increasing your d…
On the other hand, take the example from the article: the bored web developer spends "a few years" mastering Ruby on Rails. Oops, by then RoR is yesterday's news, now it's Clouds and Hadoop and Clojure and [insert technology/language/architecture du jour here]. So I think what you need to work on is not mastering something like "Ruby on Rails" but something at a higher level of abstraction... skills and habits that let you remain proficient and passionate about your craft even as the technological sands shift under you. I'm not sure how to really articulate what these are.