The first three titles were based on a running game and defense. Brady was a great game manager, and a winner. Part of Belichick's franchise
Brady became an elite passing QB in 2007, the year they went 18-1
The last Super Bowl they won was 13-3 over the Rams. I'm going to suggest that wasn't because of Brady. Sean McVay talked about how badly he was schooled by Belichick
Every player who played in New England talks about his unparalleled game preparation. Except for a couple of malcontents that were simply undeciplined
When the Patriots beat the Falcons, that was all on Tom Brady. Every other SB win had a strong defensive effort.
Brady also helped in another way, he played for far below market value, enabling the Patriots to sign more talented players.
Belichick has 8 rings. Time certainly did it's thing