“What we now normally consider the mainstream—so called realistic fiction—is a small literary genre, fairly recent in origin, which is likely to be relatively short lived. When I look back at the foundations of literature, I see literary figures who, if they were alive today, would probably be members of the Science Fiction Writers of America. Homer? He would certain belong to the SFWA. So would Dante, Milton, and Shakespeare. That tradition is literature’s mainstream, and it has been what has grown out of that tradition which has been labeled SF or whatever label you want to use”— Gene Wolfe
Not a new idea, but an authoritative source.
From this interview.