To flesh out your comps a bit ...
In Elway's case, until Shanny became the HC, the Broncos had rarely had a rushing attack that placed in the top half of the league, and it was often in the bottom 1/3rd. Shanny didn't arbitrarily begin running the ball more. In fact, in his first season as HC, he actually ran the ball less than the Broncos average from the previous four seasons. Instead, he first built a ground game that consistently placed in the top 10, if not top 5 or even best in the league - a dramatic turnaround (mostly due to vastly improved run-blocking) - and then they ended up running the ball more, a lot more.
Sure, that helped the Broncos become more consistently successful in the last four years of Elway's 16-year career. They went from a .500 club to averaging 13 wins and winning back-to-back Superbowls. But it didn't reduce Elway's average pass attempts per game at all.
With Brees, it's bee a little different, but still not directly comparable with Brady's situation.
From 2012 thru 2016, Brees averaged 664 pass attempts per season and his pass attempts averaged 63% of the Saints' offensive plays. Meanwhile, their ground game averaged pretty close to the bottom 1/3rd of the league, almost across the board.
In 2017, the Saints' ground game jumped up to top-5 in the league (1st in rushing TDs) - a very similar dramatic turnaround. And it did reduce Brees' pass attempts (to 536), and the Saints' passing ratio (to 55%). For the one year, so far.
But that didn't merely "preserve the career" of a QB nearing decline. Brees' completion percentage actually increased, his net yards per attempt increased, his sack% decreased and his interception% decreased. But not because the Saints arbitrarily decided to "run more" to help Brees out. They ran more because their ground game had suddenly become dramatically better, just like the Broncos' ground game did under Shanny.
But here's the important comp.
In 2012, Brady made the most passing attempts of his career - 641 - 23 fewer than Brees' average. Oddly, in that same season, Brady's passing attempts accounted for only 55% of all Pats plays on offense - because they also ran the ball more. They had 1164 total offensive plays that season (a record, I think) due to running the hurry-up and no-huddle almost constantly.
So, while Brees' passing attempts averaged 63% of the Saints' offense over an extended period, Brady has never been above 62%, and has only topped 58% twice in 18 seasons: 2002 and 2015 (when the OL and RB corps were both simultaneously decimated by injuries). During the time when the Saints' passing averaged six percentage points above the league average, the Pats' passing averaged one point below the league average.
At the same time, the Pats ground game has been in the top-10 in the league, if not in the top-5, in most categories for all but a couple-three of Brady's 18 seasons (including both "Guge years", as it turns out). IOW, in most seasons, the Pats have already regularly been where the SAINTS JUST GOT TO, in terms of relative ground game effectiveness.
For an opponent-specific game-planning offense, arbitrarily running the ball more to reduce Brady's pass attempts seems insane. UNLESS the Pats somehow make the ground game dramatically better, it simply doesn't work.
So, then,, how do you make a ground game that's already top-10/top-5 in most seasons "dramatically better"?
