Why write sci-fi?
Rather than answer that question directly, I would instead prefer to respond in two parts. For the first part, I submit this quote by famous Real Literature author Sinclair Lewis:
There is no such thing as a "greatest" novelist, for how can you compare Lewis Carroll with Proust or Willa Cather with Dreiser? But it seems probable to me that just now, in 1941, there is no greater novelist living than Mr. H. G. Wells. On the mountainous slopes of Thomas Mann, there are too many fogs of magic for the bulk of him to overshine the quick, plump, gaily trotting human figure of Wells.
Of all the gallery of Wells novels, from such early fantasies as The First Men in the Moon, through that panorama of Edwardian folly and ambition, Tono-Bungay, down to the last tired reiterations that it really is just too bad that Mankind won't gather in a still and spacious library and determine to do something about it all, there is no book so deeply reaching into contemporary character, so funny and yet so moving, as The History of Mr. Polly...
And now for the second part, here's a challenge: go into your nearest bookstore or library and try to find the three Wells novels Lewis mentions.
Which one did you find first?