I posited that the challenge in SF is that we consider ourselves the literature of ideas, and a repeated idea is much harder to make interesting. As opposed to, say, romance, where the core story idea shouldn't vary too much (within the defined subgenre at any rate), as the emphasis is on characters and their relationships. To some degree mystery has an analogous situation. Even fantasy, specifically big-book post-Tolkien stuff, has a strong investment in the repeatable experience of a specific flavor of escapism.
Only SF is heavily invested in permanent novelty-seeking.
And since as a field we have only recently grown past a one-generational span of memory, we're very conscious of repetition. This is how we fall into the trap which has been so widely discussed of late about losing readers. It's possible to view SF as having too much encoding, and therefore requiring the reader to reach back too far to learn their way forward. (I'm not staking a position in that fight at the moment, just making an observation.)