It gives anyone the right. The Arctic Monkey's guitarist doesn't know theoretical stuff at all, what he does know is when and where to play power chords. Now, he's made (how ever much) money off of doing this, so I'd class him as lucky to not have to learn as much as some people have had to. He won't ever make any money as a professional musician (as in session/session touring/session studio) unless he learns a load more chords, learns to read etc. Now, he could very well be sitting on a money hill, and know he never has to work again, in which case, well done to him for being in a band that people liked. Maybe it's more a case of saying, there's talent, then there's professional talent which is in leagues above normal talent. By the way man, vitalize your chart & score reading, there are LOADS of studio gigs in London at the moment. You only need one to get you on the road to success.