Thank you Ivancamp for a well thought out presentation of the path Brady has taken over the last several years. However I think both you and Andy have gotten too caught up into the minutia of what defines "declining production", and have missed the underlying question of what lies ahead for Brady and for how long.
I think you FIRST have to define what (at this stage of his career) makes Tom Brady an elite QB, and then project those assets to determine just how long Brady can stay at or near his current level.
His number 1 asset is his mind and has been since he's been in the league. His ability to process the chaos in front of him and consistently make the right decisions has been apparent since he took over in 2001. Now you add 17 years of experience and, on the mental side of the game, you have the best QB in the history of the league.
I don't believe there has ever been a QB who has had Brady's processing skills, COMBINED with the amount of experience he's had. There is no reason that for the next 3-5 years we should see ANY diminishment of that part of his game.
Now we get to the physical side of the game. This is the part where we WILL definitely see decline as Brady ages. It's just how it is. His velocity of his throws will diminsh, as well as his ability to move in the pocket. The BIG question is just WHEN we should expect to see that decline. But the fact is that as of right now, Brady's mechanics and footwork are actually better than just a few years ago. He has a better arm than the one he came into the league with, and shows no signs of reduced velocity of this throws. In fact he's improved his deep ball accuracy a lot over recent years.
But that being said, on the conservative side, I'd think 2 years sounds about right. I don't think that there are many among us, based on what we've seen over the last few years, that would think that Brady won't be an elite QB for at least the next 2 years.
Brady's 3rd biggest assets are BB/McDaniels, and the system he's played in his entire career. Given this "system", Brady's processing skills and experience are magnified because he KNOWS on any given play where his blockers and receivers are going to be and that they will be flexible enough to adjust to the changes he might have to make on the LOS. Just think about how FEW QB's have ever enjoyed this kind of continuity for so long, and how it plays into Brady's biggest assets and thus extends his potential for productive play.
I think the next issue that needs to be discussed is the whole "cliff" debate. I find it ridiculous that anyone would think that Brady production would suddenly "fall off a cliff" when his "support system" of his mind, processing skills, and team system would so mitigate against such a precipitous decline.
You can also see how BB is begining to move to make sure that as Brady's physical skills decline, he will have improved players to surround him and make sure that there is no "cliff". And to make sure that the Pats will always be in the hunt for a championship.
Brady'numbers at the start of his career, when the Pats won 3 superbowls, with Brady as a "manager". This was a time when Brady wasn't expected to "carry:" the team. Since 2007 THAT perception has obviously change. Now as Brady goes, so go the Pats. So when we start to see physical and numerical proof that Brady is in physical decline, the decline will be slow enough that the Pats chances of winning might not dimish at the same rate, as Ivancamp pointed out in his treatise
So based on that, I can easily seeing Brady as have a 2-3 year run as an elite QB, and another 2 years as a very good one. The only reason that this scenario might not come to pass is either a massive injury or if Brady loses his competitve drive.
I also feel that the day Brady feels he can't be ELITE any more, he'll hang them up, so IMHO, we will only have to "endure" one year of the "just very good" Brady