I think it has alot to do with team-style and the way it is coached.
Bill Belichik bucked the trend with that huge win streak. He is still one of the most underappreciated head coaches in the NFL when he should be heralded.
What he did with that win streak should go down in history as one of the greatest head coach accomplishments in all of sports! It's extremely difficult to put these win streaks together.
Belichick does it by putting a different team out on the field every Sunday, and the opponent has no idea what is coming. If you notice, when alot of good teams first get beat, the armor is usually cracked wide open and the rest of the league looks at that gamefilm on how to beat them. It can't be done with Belichick.
The man is a certified genius IMHO, the Vince Lombardi of our era, and combine that with a stellar front office (Owner Bob Kraft is a genius too), you are going to compile alot of Super Bowl rings.
It's very likely these two (Pats and Steelers) will meet again in the playoffs and it'll be something to witness, and it could be the rivalry of the decade.
But as far as my eye can see, I don't see Patriots slipping from the top anytime soon as long as they don't change anything at the coaching and management level. I predict they will be the Packers of the 60s, Steelers of the 70s, Niners of the 80s, Cowboys of the 90s.
Belichick IS a genius, a great game day guy! And Brady is a WISE ONE too!!!!