Perhaps the question is a bit awkwardly phrased, but I don't think the question is all that elementary. Of course, he made some killer records, but so did a lot of people at the time. But what about Miles turned him into a household name way beyond the insular word of jazz? I don't think it's really addressed in the books. There is no clear-cut answer, of course. His charisma and self-confidence/arrogance are one factor, of course, but again, he's not the only one.
Bertrand.