This is a very interesting perspective.

Though, I think technology is the big differentiating factor between movies and books. The quality of CGI, special effects, resolution, cameras, etc. are constantly improving and I think a significant portion of the younger demographic fails to appreciate older movies due to the obvious age of the films. There just isn't much evolution in how books are consumed or written. Digital books make them more accessible, but are not exclusive to new releases.

Other than technology, I think marketing and name recognition are the primary factors for selecting both movies and books because of a popularity bias. New media is heavily marketed and will likely still receive a lot more consumption.