If you think Laveon Bell's injury was the difference, you don't understand football. It begins with line play, and whomever dominates the line of scrimmage usually wins the game. (Hence the impetus to get after Brady). At the NFL level, it's about matchups, execution and avoiding mistakes. Belichick's greatest talent as a coach is to get players to NOT over-commit on plays. That's really what "do your job" is about -- stay with the assignment. Don't over commit.
And Brady compliments that by minimizing mistakes and turnovers. A huge part of his greatness is the throws he doesn't make.
Which is exactly what Alan Branch and Trey Flowers (and whichever else mid-level NFLer he gets next, desperate to win and willing to do as told by Hoodie The Great in order to taste a Super Bowl) did.
This is why people simply don't get the Pats: 30 of 53 on this roster weren't on the 2014 SB championship team. But here they are, again. It's Bill. Who else dumps Jamie Collins for Elandon Roberts .... and comes out ahead?!? He schemes well, has great assistants, and demands TOTAL commitment to the scheme. More often than not, it works.
It sure doesn't hurt that Brady has a tremendous capacity to read defenses and respond appropriately.