It should go without saying, but now, more than ever, we have an near infinite supply of art available to us. From the comfort of our own beds, we can stream a film, play the latest Mario Bros., look at the paintings housed in the Philadelphia Art Museum, and download bestsellers straight to our e-readers. A lot of people claim that all of these different forms of media are “competing” for our attention. The novelist complains about the filmmaker who steals his audience. The filmmaker decries...