Sure, but if you concede that, then the flip side of it has to be true as well, ie Rodgers has had more opportunities to win games and "be great" because his defense has it easier playing on grass instead of trying to defend opposing offenses on a fast track in controlled climates.
But besides that, playing in the elements hasn't prevented Brady from putting up GOAT numbers.
That makes no sense. The Packers playing outside doesn't make their defense any more likely to win games than the Saints. Their defense struggling to stop teams in the dome just further inflates Brees numbers, but it doesn't make him any more or less likely to win a game. If you arguing that the Packers had a better actual defense, that's a different argument.
Inside outside is a bigger deal than you are allowing for.
Brees inside
127 GP 295 TD 113 INT 69.58% 104.2 rate
Outside
124 GP 205 TD 107 INT 64.85% 91.4 rate
Rodgers inside
26 GP 54 TD 11 INT 67.51% 109.0 rate
Outside
130 GP 266 TD 66 INT 64.29 % 101.9 rate
As for Rodgers and Brady, Rodgers numbers are right in line with Bradys, he just hasn't been doing it as long.
Rodgers 154 starts 42006 yds 334 tds 79 int 64.8%
On a per start basis, that's 272 yds 2.17 TD .51 Int
Brady 263 starts 69501 yds 508 tds 168 ints 64.1 %
Per start basis, 264 yds 1.93 tds .64 ints
You keep mentioning Rodgers numbers as if they aren't even close when the truth is they just aren't close because of the number of years he's played.