In an old (Dec 2002) Locus interview a writer, Orson Scott Card, who isn't a huge favorite of mine discusses the versatility of SF
Science fiction gives writers a tool set unmatched by any other genre. We can take our tools and step into any genre and do really well, but they can't take their tools and step into ours and do anything but flounder around. Our tools include most (but not all) of theirs. We have the ability to lead readers into a world that is not their own, step by step, without pain. We don't all do it -- there's plenty of bad science fiction where you have no idea where you are and what's going on. But from Robert A. Heinlein on, we've had the tools to do it without expository lumps, with the little details bled in. We train our readers to be able to absorb the changes, the differences between the world of the story and the world they live in, bit by bit and build up the picture slowly, frame by frame. Figuratively, we've learned how to start in a small room and only open the doors as we need to open them. The world expands as we move through it and as we need to reveal it -- which is way better than the horrible prologue that tries to give you the whole big world picture before dropping you into the story. We've learned techniques that actually work.