Strikes me that there are a lot of legendary musicians in traditional music - the worlds of legend and oral transmission being close relatives. Obvious examples would be the Leadbelly "Goodnight Irene" prison legend; the Jimmy Allan, wild Northumbrian piper and horse thief legend; all the legends of traveller singers like Jeannie Robertson; the legend of Django's fingers. Legends don't have to be overblown fictions of PR machines, so "legendary"seems a fair enough label, if a tad overused.