TSR's Latest, Greatest, Science Fiction Thriller

While searching through the Players Manual of the 1983 Dungeons & Dragons Basic Set for illustrations of goblins for today's earlier post, I came across this advertisement on its inside back cover.

As you can see, it's an ad for Star Frontiers , TSR's 1982 science fiction RPG. SF – a fortuitous abbreviation – was not the company's first foray into the genre, it was the first into what is popularly imagined by the words "science fiction," which is to say, space opera filled with jumpsuits, robots, aliens, spaceships, and laser guns. On that score, Star Frontiers delivered. Though I was (and remain) a Traveller man, I nevertheless had a lot of fun with Star Frontiers, especially its Knights Hawks starship combat expansion.
What's amazing in retrospect is how well supported the game was. Over the course of four years (1982–1985), TSR published a little more than a dozen modules for it, in addition to the aforementioned Knight Hawks, a referee's screen, character sheets, and then, finally, Zebulon's Guide to Frontier Space.  That's more than Gamma World has ever received in any of its many editions. Despite this, TSR seems to have simply given up on Star Frontiers after 1985, while Gamma World kept re-appearing every so often (to increasingly little success, to be fair). Why was that?
Over the years I've entertained numerous theories, but I have no real evidence of any of them. The most likely is that Star Frontiers simply didn't make enough money to justify the effort. That's not to say it was doing badly, only that it wasn't doing as well as TSR hoped it would do, especially when compared to RPGs like D&D or even Marvel Super Heroes , both of which had a much higher return on investment during the same time period. TSR was never a particularly well-run business, it's true, but I suspect even they would recognize when their resources might be better spent on other more lucrative projects.
Again, I have no idea if this theory is true. It's just as plausible that someone in the company simply disliked the game and wanted it canned or that the main movers and shakers behind it moved on or could no longer devote much effort to developing it. Whatever the reason, it's a shame, because, as I said, Star Frontiers was fun and had some interesting setting and game mechanical elements. I would have liked to see how it evolved if it had been given the time to do so. Ah, well!