I guess comparing Brees and Brady as just pure passers is probably not an apt comparison. Brady always had a cannon arm while Brees threw a more accurate, touch pass.
Brady seems to be taking a lot of deep shots and throwing fast balls on the out routes and curls. Also, Brady's height makes it a little easier for his to see the field and get the ball out on those plays where Brees still needs to shuffle up on his tip toes and locate an open receiver.
But agreed...at some point age is going to punch Brees and Brady in the gut, so it's critical that Payton allow the running game to flourish, so when that happens - we have something to rely on. I just don't see Arians reducing Brady's pitch count and allowing the game to run through his backs. Its just not how he's made -- but then again, neither is Payton. So I guess the team with the most success down the stretch will be the teams who's coach ignores his typical pass, pass, pass tendencies.