Sorry to bring this discussion back, but I definitely agree that familiarity and “comfort” are contributors to the lowered interest in non-franchise science fiction compared to “medieval-ish” fantasy.
However, I think this can be solved. I am running Delta Green right now (Call of Cthulhu crossed with X-Files in the modern day), and everyone just… gets the setting, even with all the Mythos and Conspiracy nonsense. It’s definitely not because the setting is simple (2018, even minus the Mythos and Conspiracy, was not a simple year) I think this is because it’s set in and built on top of the modern day which all the players are intimately familiar with because they all lived it.
So I think a solution to the “comfort” problem of sci-fi is to set it as close to the modern day as possible. Andy Weir’s The Martian is the best example of this approach succeeding, I think. Even my friends who hate sci-if and science loved it and felt comfortable with both the book and the movie because it doesn’t have any wild science fiction devices or concepts, and doesn’t have radically alien politics. It’s is supposedly around 2035, but it’s practically set when it was released.
I’m plan on testing this out by running a near-future (“20 minutes in the future”) adventure game of Lunar or Martian colonization with a mix of both sci-fi fans and those less interested in sci-fi and see how it goes. No fancy sci-fi tech, just what we have in the modern day plus what we need to survive (which we already can produce today).