He won in New Jersey because he's a no-nonsense straight-talker who was a breath of fresh air after the last two @ssholes in that position, but his shtick simply won't play well anywhere west of the Delaware River and he wouldn't have brought anything (including his own state) to the Republican ticket in 2012.
Your reasoning holds for those of us with ordinary egos. But Christie is a politician; his ego is enormous and a tremendous amount of his self-worth is based in the adoration of strangers. He wanted the job and has a high enough opinion of himself to think he would get it. You're correct that he never had a chance. But you're mistaken about the other part: He was the last person in the world who believed he wouldn't get the offer.
As I posted elsewhere, and at greater length, Christie did what he did with full deliberation. Whether the reason for that was resentment (my theory) or his own reelection bid is immaterial. He did it willfully and with full understanding of what he was doing. Like an actor, he is a politician of some ability and that means that he manipulates public perception for a living. To believe that he spontaneously embraced the flailing leader of the political opposition in a moment of genuine emotion in the full glare of the national spotlight in the last 100 hours of the news cycle is like believing that Lawrence Olivier would spontaneously jump in front of a camera and lapse into Hamlet.
In any event, it doesn't matter. He has no future in the Party outside of Jersey, and unless he has an eye on a Senate seat that he'll need money for (and doesn't think the other Party will provide), I expect him to pull a Specter or have a Bloomberg moment very, very soon.