If Close Encounters had opened first, the idea of space and stories about aliens would have been lifted to a certain level of audience maturity. And I think that some of the great writers and some of the great screenwriters would have been making films in that genre as opposed to bang-bang Star Wars and Star Wars sequels. Close Encounters was, from the beginning to the end, about something far more intelligent, or intellectual, or uplifting...The first line for Close Encounters was 'You have nothing to fear by looking up.It is clear that Star Wars won, as we see with the billion-dollar release of the seventh episode of the franchise. I don't remember a sequel to Close Encounters. But that does seem to be the way of the world and Hollywood. And yet I am hopeful. The release of The Martian last year was a stunning scientific film that captured everyone's imagination without light sabers and Death Stars. And let us not forget the movie Contact, putting Carl Sagan's book of the same name onto the silver screen. And even Star Trek can be said to be a somewhat more realistic take on human expansion into space, or at least a little more hopeful that the Star Wars version of the galaxy (or some other galaxy far, far away), and it precedes Lucas' story by a decade. So cheer up, Richard.
Update: Tom Shone has an informative article in Slate that discusses the overlapping careers of Lucas and Spielberg. It is worth a look.