One interpretation of Tennyson's ballad, "The Lady of Shalott," is that great artists produce great art because they exist outside of convention, and it is their disconnection from, "normalcy," that allows them to observe life from an outsider's point of view. Those of us in the mainstream view their work as visionary and innovative because it comes from a perspective beyond our day to day experience.
Of course, to effectively communicate their observations and commentary, the artist must also be a master technician be it with a paint brush, chisel, or in Prince's case, a guitar.