Yup, if.
It hoits, as they say down there in The Apple. It hoits, and it will always hoit, but the thing about sports is that there is always a new season. There is always another chance. You lose the 1910 World Series to the Philadelphia A's and if you're a Chicago Cubs fan you say, "That's OK; we'll get 'em next year." (OK, sometimes it takes a while.)
You fail to achieve your goal? That's tough, sure, but you just saddle up and try again. And if you're the New England Patriots, you ignore all you're going to hear about a so-called "Super Bowl Hangover." You pay no attention to the people who point out, some gleefully, that of the last 10 Super Bowl runners-up, seven have not made the playoffs the following year and seven did not break .500. You will assure yourself that this business has nothing to do with your particular situation, and you will, in fact, be right.
Ask yourself. Was Bill Belichick coaching any of those other teams? Did you happen to see Tom Brady taking snaps for any of those other teams? No. So: next question.
The 2008 Patriots do have a unique situation. Only the 1972 Miami Dolphins had anything close to a regular season to compare with the one experienced by the Patriots in 2007, and when you look closer you see there was very little honest comparison. The Dolphins had a cupcakey schedule. The one big thing you can say for them is that they won the majority of their games with a backup quarterback, Earl Morrall, as opposed to their starter, Bob Griese. We know Matt Cassell and we know he's no Earl Morrall, so we must give the Dolphins their due on that matter.
The 2008 Patriots will start the season as motivated as any team in NFL history. Belichick will be as dedicated as any coach in NFL history, his prior selves included. The team and the coach are fully aware of something far too many of their blindly adoring fans refuse to grasp, which is that they are perceived by great swaths of sports-loving Americans as outlaws. Note I did not say they are outlaws, only that they are perceived as such.