Reason #1: Expanded Demographics
I asked Jason, a close friend of mine, if he ever played games.
"No," he said. "If I'm going to invest my time in entertainment, I want it to have meaning. There's no meaning to games."
Upon further questioning, I learned what he meant was that he wanted entertainment experiences that also contributed to or enriched his life in some way; experiences that weren't just fun diversions.
My friend speaks for a vast group. There are many more people who watch film and television than play games. Many of these will never be lured into playing games until games begin to offer the emotional range and depth of the entertainment they're used to enjoying.