Because of all the hype. We are seeing all the action sequences in the trailers. What's left for the movie?
Plus, it's an odd numbered trek.
Although this rule went out the window after #10.
The name, "Star Trek", carries a bit of a stigma with it. There are those that like it, those that don't and unbelievably, there are those that have never heard of it.
If this is a reboot, and they want to get new people to watch, how do they eliminate the stigma that comes with the name, Star Trek?
Those that don't like ST, won't watch, and those that have never heard of it, probably still haven't heard about it. So that just leaves those that like it. Which are the fans. So who are they trying to get to watch the new ST? They know the fans will, even if it's just out of curiosity for some.