Scott Adams is definitely not famous because "he is an ok graphic artist and has an ok humor". He's famous because his satire was fairly unique and very sharp. I think he's very talented in the humor department; in addition to his creating invention and sharp wit, very often his strips have two punchlines - in the middle and the last panel - which take twice as much effort as a "standard" comic strip.
His drawing skill didn't/don't really matter, as a matter of fact, he wasn't particularly good at the beginning, and his style is generic and simple anyway.
It's very unlikely that somebody with "he is an ok graphic artist and has an ok humor" will get his success just because of such qualities.
¹=A very ridicolous example of whom was when he was proving that Trump will be successful because, based on his observations, leaders who were great in the long term, typically had a rough start. Can't find the post.