Noam Scheiber senses a lack of urgency:
Newt obviously doesn’t want to do the things you generally have to do if you want to become president. More to the point, I don’t think he even wants to be president—by which I mean, undertake the grueling, 24-7 challenge of running a country. It’s much more of a grind than his current lifestyle of book-hawking, seminar-giving, and extravagant vacationing. (I think he’d be happy to do a job where he gets called "Mr. President" but someone else takes care of the demanding stuff.)
My sense is that what’s motivated Newt these past few months is just ego—a determination to prove that he could be president if he really wanted to, that the idea isn’t patently absurd, the way most commentators and even his own staff concluded this summer. But having proved his point, I don’t think Newt has much more to play for. If he’s campaigning like a man who’s already done what he set out to do, that’s probably because he has.