I've been under the weather this past weekend, and as I've demonstrated in the past, I tend to deal with such misery by doing thought experiments. Since a comment by Erin on my musings on Sci Fi RPGs brought my attention to this particular thought experiment, that is how I spent my weekend. Since Scott of Huge Ruined Pile has done much of the hard work with the rules themselves, I busied myself with the Inspirational Source Material at the end of Molday's Basic D&D. I felt entirely justified in doing this, because I vividly remember staking out literary territories that inspired and informed D&D worlds that my friends and I built and played in when we were first trying to feel our way through the game.
I did give myself a limitation, however. I only allowed authors and works that I had not read before. As I was ill, I was limited to free on line resources. One of the first authors that I had success with was Leigh Brackett and her fabulous tale "The Black Amazon of Mars," which was the original title and version of The People of the Talisman — one of the titles cited by Moldvay.
Please note, Leigh Brackett is a sci fi writer and "The Black Amazon" is a sci fi tale. Interstellar travel is a given. The story begins with the aftermath of a gun battle. Mercury, Venus, Earth and Mars are all mentioned as places the hero Eric John Stark has been.
Which brings me to the point of this post. Having been completely drawn into Brackett's vision of Mars and her version of the solar system and inspired enough to put on paper some kind of D&D version of this vision, I have come to the conclusion that I think James' question makes an erroneous assumption. Despite the sci fi source material, D&D (especially Moldvay's edition) is a perfectly suitable game with which to create a world and universe inspired by Brackett's work. Thus, D&D is a science fiction RPG, and the most wildly successful one, at that.
We forget that the classification of sci fi and fantasy as two separate genres is a fairly recent phenomenon. Although James is very good at mining and giving homage to the past, his question fails to remember this reality. Which brings me to what I think is the real answer to his question. D&D has been as successful as it has because it so good at pastiche. It is perfectly capable of being high fantasy, dark fantasy, pulp, sci fi, horror, etc. It doesn't matter what you want to do, D&D is quite capable of handling it. In contrast, games like Traveller are too much tied to their niche within the sci fi/fantasy spectrum. In other words, you could do the Third Imperium with D&D, but you couldn't do Greyhawk with Traveller. That narrow focus necessarily limits their appeal and thus their audience.
So the real question isn't why these other games have failed, but rather why D&D succeeded. The answer is the wonderful goulash that sci fi used to be and the fact that D&D was not only was born out of it, but embraced it.
38 minutes ago