Agreed in that Montana is the only guy who has a legitimate argument. Bradys stats though, even in a pass happy QB protected era, are more impressive than Montanas were in his era.
You guys are high as a kite if you don't believe QBs are judged, in large part, by SB wins. There is simply no other position on any other team sport in the world that is held more responsible for their teams success as an NFL QB.
If you take SBs completely out of the equation, which you cant, then theres no peer to Dan Marino. The numbers he put up in that era are mind blowing. He threw for 5k in 1984 - it wouldn't happen again until 24 years later.
BUT. Marino doesn't even sniff the conversation. He is barely an afterthought because of the goose egg he has in the SB column.
Brady
Montana
Manning
Brees
Unitas
That's how it stands in my eyes. Brees wins another 1 or 2 and he moves into 2nd because his stats are just herculean to the point where it makes it hard to argue against him. I think another 1 or 2 SB wins and you can then start using things like Brees' defensive lack of help and division, conference, etc to make a legitimate case that he is the GOAT and Brady was a product of favorable conditions. But with Bradys combination of stats and rings, right now it is what it is.