I'm going to guess that SW novels make the authors more money than Star Trek novels. I don't know that for certain, but the Star Wars novels are always much higher in the charts at Amazon even if they cost more.
We can probably safely say that Star Wars novels make the owners of Star Wars IP more money than Star Trek novels do for Star Trek's IP owners. Either way, the novels are work for hire and copyrighted by the IP owners, not the authors, so nobody's making Stephen King money.