[jacobolus]

I think when you say “how far removed it is from present day society”, what I hear is rather “how rich, subtle, and believable its characters and societies are”. Because real societies are rich and textured, full of contradictions and moral ambiguities, characters with complex motivations.

Snow Crash has a bitmap pattern that can hack into programmers’ brains and knock them unconscious and the complete collapse of nation-states and The Diamond Age has pervasive nanotechnology. Dune has gigantic sand worms and psycho telepaths. China Miéville’s books have giant mutant bird-people. Speaker for the Dead includes aliens, artificial superintelligence, faster-than-light communication. &c. &c. &c.

“Real literature” (any way you define it) has many of the same building-blocks: gods (The Illiad), fairies (Twelfth Night), voyages through the underworld (Dante’s Inferno), characters who hop from one body to another (Death in Venice), interesting new interpretations of language and cognition and radically different cultural/social customs, etc. etc.

But works (including those set in space) that oversimplify and preach at us, or just serve as fantasies for us to insert ourselves into as passive escapism are little better than Horatio Alger novels, or, say, the trashiest kinds of romances. They can be fun, but ultimately they don't have quite so much staying power.