In my humble opinion, the reason Star Trek's "prequel" is succeeding where Star Wars failed is simple. Star Wars, you can go into the 3 prequels and you don't have to worry that Obi-Wan or Anakin are going to die. Why? Because we've seen the late Sir Alec Guiness portraying the same character. Star Trek...simply put, while it is an origin story, it negates the baggage of, "Oh, I know Kirk has to live for at least 75 years so he can die on Veridian III" due to the time travel creation of an alternate reality(something that has happened plenty of times in Star Trek lol). This creates the notion that ANYTHING can happen to these characters now. Their fates, unlike the fates of Obi-Wan and Anakin in Episodes I, II, and III, are not fixed.