“Thus, traditional criticism’s charge that science fiction isn’t, in general, ‘literary’ because science fiction writers don’t focus on or have the artistry to deeply delve into character misses the point that science fiction isn’t about character, it’s about ideas. And therefore, science fiction should be judged by a different set of criteria than mundane mainstream fiction is evaluated.”
In “Saving the World Through Science Fiction - James Gunn, Writer, Teacher and Scholar” by Michael R. Page
Don't critics ignore SF because there's far too much of it, and the vast majority of it - like any sector of genre fiction - is a bit safe, geared more to selling to a niche of fans than the mass market? Certainly SF fandom is obsessed with genre distinctions (steampunk, space opera, mundane, whatever) that have absolutely no currency in the mainstream world - just like crime fandom (maybe to a lesser extent) worries about distinctions between golden age, hard-boiled, procedural and so on.
In both cases the really good stuff, the stuff that transcends the formulae and has something worthwhile to say - Atwood, or Houllebecq, or Alan Moore, Ballard, or Gunn - it "does" get noticed, it's just that people don't call it SF anymore.
If you're into SF Literary Criticism, read on.