In no particular order, off the top of my head, I'd argue these guys are better pure QBs than Tom Brady.
Jim Kelley
Roger Staubach
Joe Montana
Aaron Rodgers
John Elway
Dan Marino
Drew Brees
Peyton Manning
And that's not even including a couple from way back. Johnny Unitas and Otto Graham.
I think any of these guys if put in the same situation that Tom Brady had could have accomplished what he did. Maybe even a few others, like Troy Aikman, Terry Bradshaw, Kurt Warner, Warren Moon, Steve Young.
I'm not saying each and everyone of these guys are better than Tom Brady. It is next to impossible to judge strictly QB talent. Some are better at reading defenses. Some have better throwing arms. Some handle pressure better. Some are more moble. Etc... Only that I think they could have had a damn good shot of accomplishing what he did if dealt the same circumstances. The media and fans prop Tom Brady up like nobody else could have done what he has. I disagree.
Jim Kelly - No way.
Aaron Rodgers - I actually rank him higher than most people I know. I hate him too much personally much, though. If he leaves the Packers, maybe I'll reconsider.
Drew Brees - Throws too many INTs for my liking.
As for Marino, Elway, Staubach, I can't argue that Brady's definitively better, but the fact that Brady's been able to succeed with four cores of players over his career puts him over the top.
Montana is my #2 because I think Montana is the greatest playoff QB of all-time. Greatest Super Bowl QB of all-time. I'll give Brady the edge, though, because Montana had the benefit of the greatest NFL player of all-time along with other supporting cast. Walsh and Belichick are a wash...and cuz Montana is a 49er. Fuck him and all their fans.
Steve Young is an interesting one, but he's a 49er.
As for the argument of Brady playing in a pass-friendly and pussified game, sure. I agree with that. But today's game also has players 30% bigger and faster and requires 365-day, year round conditioning. Today's game is also more sophisticated than the past. Could yesteryears players handle this? Tough to argue about this era vs past eras, so I weigh it moreso on success amongst contemporaries. Bottom-line, nobody's come close to Brady's accomplishments 2000-2010, 2011-2020 and surely not over 2000-2020.
Lastly, you can say Brady had Belichick. How much of an advantage is Belichick over Walsh, Landry, Shula? Is that advantage worth more than the supporting cast advantage Montana & Staubach had over Brady? Marino and Elway (except for late 90s) gets shafted in the player supporting cast dept.