2312 - Kim Stanley Robinson
As with all his books it says more about the human condition and society than almost all "literary fiction", and oh yes his prose is absolutely beautiful. If the literary world didn't look down on anything labelled SF he should win loads of awards. There are several other anthers that do societal and political stuff really well in an SF context (eg Ken MacLeod on left wing politics) but I don't think there is another author whose prose can match.
You remind me of a friend's comments, way back in the days of my callow youth, that SF was never literature. Summing up his argument in dismissing my suggested examples of literary SF, his circular reasoning was "SF Isn't literature. If a book can be described as literature, it isn't SF because SF sin't literature"
I am further reminded of the adulation that flows towards 'literary' authors when they come up with 'original' ideas that have been done to death by SF writers. 'Time's Arrow' was preceded by Dick's 'Counterclock World', and 'Children of Men' by Aldiss' 'Greybeard'.
And there is the story of George Lucas, in the middle of trying to sue 'Battlestar G' for plagiarism, receiving a call from the SFWA.
"Hi, George, it's the SF Writers of America here. How's the lawsuit going?"
"Why are you interested?"
"Well, if you win, we'll sue you for the same thing"