From the beginning of the 70s until today, you will rarely see a 'great' pro football coach without a great QB.
Every once in a while, a team can win a Super Bowl with defense, but rarely, and it is not repeatable.
In today's pass and tab version of flag football, the QB is the KING, the coach is important, but you can't coach a great arm from a chicken wing.
True all dat, but one of the greatest arms and coaches ever, Marina and Shula, could not get a superbowl win together.
The NFL is not a beanbag league, nor for sissies.
So I gotta give props to dynasties like the Steelers and Pats.