You raise an interesting question, is Wars basically something for everybody whereas Trek is a niche product?
I think that in theory a classical story like the one of Wars should appeal to more people than a science-fiction franchise. But in practice I think that Trek has attracted more people than it should "in theory".
The beauty of sci-fi is after all that you do not have to be a sci-fi nerd to love the genre. I personally was never into it as a kid but then I watched a piece of VOY with a friend, I stumbled over classical authors like Wells and Asimov and at once you notice that you are into this type of fiction.
Yet I wouldn't call myself a science-fiction fan. I just "accidentally" like some sci-fi stories and I think that the mass appeal of Trek works similarly. Yes, it is sci-fi, but that is not its key defining feature and many people (admittedly a bit of a wild guess) who watch it most likely care about good TV and not about seeing a sci-fi show.
The point about attracting new audiences, well, some friends of mine have also never been into Trek but love the new movie. Nothing against them but it is quite obvious that STXI has sacrificed quality for mass appeal in order to attract these people. You do not have to love or hate the movie to be honest about what it is, a dumb enjoyable popcorn flick.