I think one of your maybes has some validity per this-
They’re just not that good anymore, really. They’re not good enough to be forgoing field goals and they’re not good enough to win on the road, and they are certainly not good enough to win the Super Bowl.
From-
A comprehensive breakdown of the Pats
http://www.boston.com/sports/columnists/massarotti/2009/12/a_comprehesive_breakdown_of_th.html
Boston is a pretty rabid sports town and the radio talk shows have been dissecting the Patriots every which way over the past few weeks. The most perplexing issue is the team’s terrible performance in the second halves of games; both offense and defense seem to go comatose. Whether this is a function of poor reactions on the part of the coaching staff or of simple player fatigue is unknown. Other parties are commenting on the overall predictability and rigidity of the offensive game plans. The third point of view is that the defense, which lost three linch-pin players (Brusci, Vrabel, Seymour) before this season just isn’t as good as people like to think it is; I think that poor defensive coaching is also playing a part. Without by any means discounting the above observations, it’s also fair to say that the team’s run of success has cost it in terms of being unable to acquire top quality players in recent player drafts.
It appears unlikely to me as well that the Patriots have any realistic chance at the Super Bowl ...