Alternative facts
I don't even see the point in this thread unless we are all gonna just laugh at the suggestion that Brees might be the GOAT. It's readily apparent Brady is #1. The players unanimously say it. The analysts basically unanimously say it outside of noted clowns like rob Parker. The fans who don't hate Brady or the patriots unanimously say it. Even most of the ones that do say it now. It's as much as a fact as the sky being blue or the grass being green. Sure you can say the grass is purple but everybody is gonna point and laugh
The sky is only gonna get bluer over the next couple of years too
For the record, I am a Patriots fan and I think Brady is the best of all time. However, at one time in history, everyone was saying that the Earth was flat (and Kyrie ****ing Irvin still do). They were wrong.
What a deeper analysis of the stats shows is that Brady is, at worst, Brees's and Manning's equal from a production stand point. These three guys are very good comparables because their career pretty much perfectly overlap. So, at worst, we can say that, statistically, Brady is one of the three best of his era. THEN, if you add winning, well, he stands alone. If you wanted to add a guy like Aaron Rodgers in the discussion, you would have to compare him from the day he became starter to Brady from the day Rodgers became starter (on a average per game basis). If you wanted to compare Brady to guys that played before him, you would have to find what the average QB's per game averages were during their careers and what the average QB's per game averages were during Brady's career and calculate how much better than average they are on various metrics. Even then, you wouldn't have perfect analysis as some eras are better for QBs than others. You would have a more compelling argument though.
Basically, what we can determine without a doubt is that Brady was at the very worst as good as Manning and Brees statistically and that he won much more than they did. It would then be fair to objectively call him the best QB of his generation. When it comes to "GOAT", well, yeah, he has the better numbers and won more, so, it is a natural thing to thing he is the best. However, to REALLY prove it, we would have to dig deeper. Also, I guess we would have to define context (teammates, opponents, league trends, etc) much better. I have no doubt such a study would show that he is the best, but we could be surprised.
TL;DR: As much as we love Brady and think he is the best, proving it OBJECTIVELY isn't that easy.