Most Star Trek fans will watch JJ Trek because it's Star Trek. Quite a few didn't like the reboot, and may well not watch In to Darkness. While the reboot bought a lot of new Trek viewers to the cinema, lets not pretend that Star Trek 2009 made a load of money for the huge, hyped up blockbuster that the media and Paramount were trying to make it out to be, because it didn't.
Paramount are now making Star Trek movies for an increasingly dwindling audience. Outside of Star Wars (if you can call Star Wars sci-fi) proper science fiction has always been a hard sell. I caught TWOK on CH4 yesterday just to remind myself what a proper Trek film should be. While I quite enjoyed Trek 2009, and am reserving judgement on In to Darkness, JJ can only dream about making a Trek film as good as TWOK. It's possible he could if someone gave him a good enough script, but the Early Learning Centre for Writers run by Kurtzman and Orci are never going to him that.