I have known a few of those who have little or no training and are amazing players that can do about anything. I think they know plenty about theory. They just don't speak the same language as others. Is theory the study of the nature of music or the study of the language used to define and discuss the nature of music? I would argue the former. Those who are self-taught, ear-only phenoms are no less educated than the most brilliant PhD on the planet. Their knowledge is proven in their playing. They just think the tonic is something that goes with the Gin.