Some guy wrote a book about spygate. I heard him on the radio and he said that the Patriots figured things out matching hand signals and audio to the point that Tom Brady knew with 75% certainty what play the defense was running. It's not like Brady was lining up with 2 TE and running dive right, the guy was lining up with 4 WR and throwing. Imagine lining up with 4 wide and knowing if they are blitzing, or playing man, or cover 2 etc. It was like a video game out there for him.
Then when the Patriots had coaching turnover, they said they HAD to hire lackey's and unknowns. If they hired Cam Cameron what's the point of risking his reputation and knowing the other teams plays? They hired unknowns like Josh Mcdaniels who would SHUT UP, go along with it, and be able to exploit the other teams defenses they already knew.
The case with the NFL lasted 3-4 days and then a week later they destroyed evidence and tapes. The guess is that the commish said look - we aren't giving any trophies back, everybody needs to STFU and maintain the integrity of this 9 billion dollar per year business because that's what it's about in the end, money.