I think the article explains that Adams "turned bad" because it is the sad consequence of him being smarter than the rest of the people. I'm pretty sure that someone who has time to lose can got through the article and pick up all of the quotes about how Adams was clever and the managers were so dum.
No, the article argues that Adams was good at one very specific thing (writing silly comics about the workplace) and bad at everything else. It's very clear on that point. It argues that later in life he lost his self-awareness of his own ineptitude and began to falsely believe he was smarter than everyone.