I majored in Music Ed a lifetime ago. The other year I got this humble little book (at either Borders or B&N's) called "The Zen Guitar Method" and it's really eye-opening. It's not instructions how to actually play the instrument, it's all about the mind-set of a musician, an approach to music.
The first 'exercise' is to play just one single note, but with all your 'soul'. (Try doing that on a Piano when you can already play Bach fugues!)
I'm less of a musical snob nowadays. You don't need to read notation to play "folk" music (which is what I think Rock n Roll really is, a type of folk music developed in the era of electronic amplification and recording)
Look at Rap; one guy's spinning records while another guy's just talking- no one's playing an instrument or even singing!
(bet the musically "illiterate" rock guitarists don't look so bad next to that?)
But it's another genre of music like Rock that touches millions of people.
(I don't "get" Rap myself, but I know people who are absolutely passionate about it)