If that's true why not hand off ST to someone else and you have the best of both worlds. I suspect there is more to the story than "I'll get to it when I'm ready"
Probably because no one else wants Star Trek. After Enterprise ended, Paramount and CBS were content to let it lie, and in fact had even rejected another movie proposal from Berman. It was a dead franchise being mocked bu pop culture pundits all over the internet. Then JJ Abrams walks in, still basking in the success of Lost and now has connections with Paramount thanks to having just directed Mission Impossible 3. He now has his choice of projects, anything he wants, they'll make happens He pitches ideas that eventually become Cloverfield and Super 8, and then adds "and one other thing: I want to do a Star Trek movie." Paramount dare not say no to him, and so even though only a year has gone by since they turned their backs on the Trek, Paramount greenlights a new Star Trek movie to be directed by Hollywood's rising star. And since that did pull some money in and made people stop making derisive comments about that "terrible prequel starring the guy from Quantum Leap" Abrams pretty much has control of Trek until he wants to give it up.
At least that's my take on things based on nothing substantial. Just a cynical intrepretation of how things played out.