Do you think most authors of graphic novels have been to school? To me it seems like an innate talent, either you have it or you don't and trying to relearn how you do something would take away from your talent.
Maybe some of them took a degree and developed their talents to the fullest. Some may have just taken extra learning through special studies. If you have the talent, you must try to develop it to the fullest.
I think some have been able to improve their skills with a college education but at the same time I don't think it's something you can learn only by going to college. You have to have some sort of skill already, in my opinion.
I would think a lot of them don't have degrees and perhaps some of those who do pursued it because they didn't have quite as much of a natural talent. When it comes to the arts I feel like too much refining ruins your personal expression.
The artists or the writers? Or any of the other people that help a comic book come to life? I bet they all went to some kind of college, most likely art college, and I don't know how that's a bad thing. Art's like every other kind of job: you need to work hard at it and try new things so you'll be better at it than you were before. "Personal expression" is nice, but if you don't know how to do shading and coloring and whatever you won't get any work. College will teach you all that.