What writers of fantasy, science fiction, and much historical fiction do for a living is different from what writers of so-called literary or other kinds of fiction do. The name of the game in F/SF/HF is creating fictional worlds and then telling particular stories set in those worlds. If you're doing it right, then the reader, coming to the end of the story, will say, "Hey, wait a minute, there are so many other stories that could be told in this universe!" And that's how we get the sprawling, coherent fictional universes that fandom is all about.