Good question! I think Americans have a museum mentality about culture: once something is good, it needs to be preserved against time and change. I think 'low' culture, like Star Wars and Marvel, etc., escapes this a little better, and so is able to be reinterpreted more often. The Godfather became 'high' culture almost immediately, so it was preserved and mothballed. We need to get away from this mentality in popular culture: Star Wars and so many other things need to live and breathe and adapt.