Yeah, there were quite a few wargames with this theme around at the time, or similar ones. There was Godsfire, Stellar Conquest, etc. which are basically spins on "Hammurabi in Space" (Hammurabi was a simple empire building game for one player which was invented in the '60s on some large timesharing systems and formed the basis of MANY of this ilk of games).
Starships & Spacemen was a direct response to Traveller. In fact I think their blurb even made some sly references to Traveller and trumpeted the various sci-fi themes that were better addressed by their game, supposedly (IE robots mainly, but also aliens). Of course Traveller did fairly quickly cover those subjects, and for whatever reason S&S soon faded from the scene. I don't recall that FGU even put out any adventures or supplements for that one. Frankly I've not ever even seen a copy, let alone anyone playing it.