I was reading some things about a completely different topic and sport. One guy made the observation: If one opponent knows what the other opponent is going to do, that guy is going to win 80% of the time.
That's why Bellichick is so big on filming teams practice. Its an incredible advantage.
People like Garret will bring up execution and they are right. If you complete every pass, pancake every block, beat every blocker on defense, etc. you will win and no scheme will stop that. However, with two relatively equal opponents, knowing where to go gives you a huge advantage in winning those 1 on 1 confrontations. Defenders jump routes, they jump into holes, etc. WR's know where the soft spots in zones will be. It makes it really hard to execute when opponents always hit you where you are weakest and know where you are going.
Getting back to Dallas, the 90's Cowboys were one of those 20% that were so good they could win when you knew what they were going to do. Even with that, they ran most of their plays out of the I and did all kinds of zone blitzes. Teams might have known all their plays but they gave away *nothing* pre snap.
I think Jerry wildly underestimates tactics and coaching because of how dominant the early 90's Cowboys were.