Here's what gives me perspective: every year teams that could we. The Super Bowl don't win the Super Bowl. They lose on a freak mistake with thirty seconds left, or a couple of bad calls, or their opponent playing a bit over their heads because their hall of fame emotional leader is retiring, or whatever. Or they go undefeated and then lose to an inferior team in the Super Bowl just because. Or they dominate a team with a quarterback who can't even throw the ball only to give up an eighty yard td on the first play of ot.
That, of course, is the entire reason why people watch football. But it doesn't prove that a team that won 11 games in a row actually sucked, or that the best qb in the league should retire.