Here’s my thinking. Before we call something a genre, it should be able to stand on its own terms. For example, a romance film/book is about a romantic relation. A war film is about a war. Dramas are dramatic. Comedies are funny (though the original definition of comedy was basically just a drama with a happy ending). And so on. The point is that each of these genres is capable of defining itself and it does not need help from any other genre to create a complete story. In other words, a drama does not need to rely on a romance or a war or an action story to come up with a complete story that is dramatic. Romances, action films, even Westerns need not piggyback on any other genre either.
But science fiction is different. Most of what passes for science fiction does in fact need to piggyback on other genres. Indeed, in most science fiction movies, what you really get is a standard drama, romance, war film, action flick or some other genre being acted out with science fiction trappings. And when you think about these films, you quickly realize that the film could easily be de-science fictioned with little change.
Now it’s true that not all science fiction falls into this category. For example, some science fiction stories are specifically about science fiction events, like the effects of time travel or cloning or alien visitation or films about the exploration of black holes, wormholes or other natural but not common phenomena. But those films are surprisingly rare and often inject subplots from other genres to make them watchable. So should science fiction be considered it’s own genre?
Why does this matter, you ask? Well, I think it matters in particular to writers who may be considering writing science fiction. Unless you’re writing a specific science fiction plot, like a time loop, then you really should learn the rules of the other genres you need to piggyback upon. I think it also gives us another way to look at science fiction and to consider why so many science fiction films fail.