In most parts, everything, whether it's music, film, books, whatever the subject may be, cultures used to operate like this over time. There are many people who could be seen as really central to the existence of that art form and then time plots along. Certain candidates drop by the wayside. And eventually you get down to only one artist remaining. That person ends up becoming interchangeable with the art form. John Philip Sousa being this example. But we don't live in a rational world. It's going to happen for other more capricious, more arbitrary motives.