This is a very interesting debate. I'd like to contribute, based on my experience in both college and in work.
The same questions about whether or not going to art school equating to good art/artists can be echoed in the medium of music. And there, the argument goes both ways as well. Studying music theory and performance/instrument technique can improve your ability overall, but that won't necessarily guarantee greatness. However the study of music theory is a basis, a common language, for musicians to communicate around, even if it's commonly decided that the language is to be abandoned altogether. The point is that there is a conscious understanding and rejection of the rules. THAT is empowerment. I have seen musicians develop w/o musical training and become very good musicians at what THEY do, but not good allaround musicians and generally slower learners than their studied counterpart. This is my experience with music school.
Then I dropped out and started learning Web design/development.
As an unschooled "designer", I don't know anywhere near as much about art as a student or graduate. I don't claim to be an expert in color theory, design, typography, or anything pertaining to the field of Web design. But, based on my self-energised portfolio, I can get a somewhat steady stream of professional work to keep me afoot. Here's an example of NOT studying and just doing. Outside of what you might think of my design, whether it's good or bad, etc, it's an example of how you don't need to be a classically trained artist to make a living.
I think the underlying essense to artistic greatness, no matter what the medium, is found in dedication and love for the medium. A profound obsession with it to the degree that you want to know all you can and spend as much time as possible immersed in it.
Jeah.
