One problem with both modern sci-fi and fantasy is that people think that settings, fantasy races, sci-fi technologies, blah blah blah, all that content, exist for their own sake. They don't. They're devised to explore literary avenues, the human condition, speculate about the future or how people would act in alternate worlds, as a vehicle for allegory, and a number of other things, but not for their own sake. Both genres make this mistake in modern times because your typical "geeks" get caught up so much in settings and franchises that they don't realize that those things exist to serve an artistic purpose.
For example, the Star Wars universe (as originally depicted) served as a vehicle for a sort of epic hero story, but set in a different sort of alien world than normal (IIIN SPAAAACE), with a sort of mysticism to it (the jedi basically being the wise monk type) serving up allegory and character development. It all existed for some artistic purpose, and were means to an end, because that's sort of how fiction and art work. Contrast this to the Star Wars prequels, or how a lot of fans seem to view the setting, where the Jedi are basically just a bunch of badass killing machines and this (and other aspects of the setting) mostly exist for the own sake in a set of action movies with meandering plot that didn't really seem to signify much of anything.
I'm not familiar enough with most popular fantasy works to say much about them, but the same sort of thing applies. There's this sort of cargo cult writing trend going on, where people ape the superficial aspects of works without realizing why those aspects were even included in the first place. Hell, in the case of Star Wars, the series did it to itself.