I don't think theres anything that notable about that. He quit producing rather than risk public dislike, was out of material, or just tired of doing the strip. If he really had an issue with space constraints, liked his work, wanted to keep doing it without marketing influence, etc he could have tried other steps. For example there are many successful online comics today such as penny-arcade and they're not all merchandise driven. For my admiration he would have been an innovator and not just given up. Unless he just lost interest in that strip, then I'm glad he quit.