Would he have put up the numbers he has on the Browns? This hurts to say, but probably close.
No, not close. Not anywhere in the vicinity. He's just not that good, and that's the point.
Any QB gets worse with a bad team, so your entire Brady argument is a fallacy.
My point is while Brees and Rodgers would not put up the same stats with worse players, the drop off wouldn't be that significant. However, with Brady, the drop off would be severe, because the talent around him is what carries him to the stats, and without it he'd be another average QB.
Everything you're using against him - your stupid "what ifs" - apply the same to ALL QBs.
Except the other QBs considered great have more talent and ability than Brady does, so they wouldn't drop off nearly as much. That's the point.