You know all those Big Name authors who writes books with
time travel, or about
dystopian futures or
genetic engineering and then insist what they're writing is Literature and not science fiction? I think they're onto something.
Science Fiction is not, in and of itself, a genre
per se, at least in my head. It's a landscape. Say sci-fi to anyone and the first thing that will probably come up is ships grandly floating through the void. But that's just a place. What
happens in that landscape defines the story. Star Trek? Gene Roddenberry pitched it as "Wagon Train to the Stars", and more often it was a flat out morality play. Wrath of Khan could be described as "Horatio Hornblower in Space" (note the uniform change between that movie and ST:TMP, with all the military braid and brass added in). Firefly is explicitely a post-Civil War western. Mil-SF requires litte explanation, nor Planetary Romance.
Even so-called "Hard SF" is always about
more than just making observations about pretty spaceships flying around. Heinlien wrote a family comedy with
The Rolling Stones and explored the nature of duty in both
Space Cadet and his later
Starship Troopers. Asimov's
I Robot stories were mysteries at their heart, made more explicit by the time of
Caves of Steel. At his most cardboard even Clarke's books were about men overcoming obstacles, either to build a great engineering achievement (
The Fountains of Paradise) or exploring and examining a a strange alien environment (
Rendevous With Rama).
Even my Big Damned Sci-Fi Novel is an homage to the great treasure hunt novels of the past, most specifically the
The Treasure of Sierra Madre. The spaceships in it are background, a comfortable environment so the readers will have their assumptions set, which make overturning one or two of them all the more fun.
So maybe those so-called "Literary" writers are onto something after all.