I disagree. Every year there are a handful of teams that have a chance. I realize it is quite a feat, but it is not nearly as insurmountable of a record as some might believe. Key injuries to an opponent, location of games, matchups, etc, have a bearing on the likelihood of it occurring.
Four teams have a theoretical chance of going undefeated. Right now, the Cowboys, Colts and Patriots are clearly the best teams in the NFL. The Packers are perfect so far, but unless they get a running game going, they are going to have a tougher path to it than the other teams.
I'm not saying any of these teams WILL be 16 and 0. But a team is likely to do it in the next 10 years. The Patriots are primed to get there if they beat the Cowboys in Dallas two weeks from now. It is clear that right now, that the Cowboys, Colts, and Patriots will be favored in every game they play, other than when they play each other. If the Cowboys beat the Patriots, who could you point to and say that they will beat the Cowboys if the Cowboys get to 6 and 0?