[Threshold]

I think one of the main reasons games tend towards science fantasy is because science fiction is really hard. Good science fiction requires some pretty serious understanding of complex disciplines: physics, chemistry, quantum mechanics, biology, chemsitry, etc.

That is a tall order for anyone, and when you add that learning curve on top of the difficulty of creating a mud, I can see why so many people hit a wall and just say "ok, it all works because of nanobots!"