Marketable just means somebody will pay you for it. All of your examples were extremely marketable. The fact is that since poetry, art, and music scale so wel

Marketable just means somebody will pay you for it. All of your examples were extremely marketable. The fact is that since poetry, art, and music scale so well, we only need a few professionals and therefore only truly exceptional people can do it. Why does a mediocre artist somehow have more value than a mediocre basketball player, for example?