Another measure of "being mainstream" is if Joe sixpack/Jane Whitepicketfence actually knows and idolizes certain (real) people in that particular industry(JK Rowling and Anne Rice for books, celebrities in movies and TV, various artists for music, Dan Rather, Tom Brokaw for news etc.) . The closest person videogame industry's got is probably Miyamoto, even then it is somewhat limited. I suppose Bill Gates kinda counts but he's well known for other things.