Real football? I don’t think there’s been anyone quite as dominant there as the ones we are talking about.
No, I don’t think there is, but cricket could arguably cite Don Bradman, and cricket has a considerably larger global fan base than any US sport.
And none of you has even mentioned Kevin Martin.
Were Bradman’s teams significantly better than other teams of the day?
I ask because, for example, Bill Russell led teams that won championships over and over and over again, while Wilt Chamberlain, who was a freak of nature doing incomprehensible things on the court, did not.
I was replying to a post about Don Bradman!
Just dropping into this thread to utter the name of God: Diego Armando Maradona.
I know I’ll never convince you but it’s ok, because you’ll never convince me either 
I’m not entirely sure it matters in cricket. I would suppose, by having Bradman on the team, that whatever team he was on was probably better, but a cricket interaction from the batters perspective really doesn’t matter what team is behind him, I don’t think. It’s him vs the bowler and the other team’s fielders. Just like in baseball if you had a career .500 hitter, does it really matter that much what team was behind you? (I’ve seen one comparison that Bradman’s achievement would be like batting .585 in MLB over a career, though I’m sure there’s a few ways you can do the math.)
ETA: Actually, I found a better number that seems more reasonable: .392 batting average over a career.
Actually, I found one I think is better saying it’s more like .392, using standard deviation as the metric for comparing athletes’ stats in different sports. Donald Bradman was calculated at 4.4 standard deviations from the norm. The equivalent in basbeball would be .392 batting average.
Now granted, most baseball fans today consider batting average a flawed metric in evaluating hitters, but that would be far beyond the current leader in career batting average (Ty Cobb at .366 career BA).
Maradona was fantastic, no doubt, but there are always arguments between him, Pele, and Messi.
Same with Jordan, James and other NBA’ers…
No one really argues about Gretzky. He’s always the best player in NHL history.
Well, yeah, but those that argue against him are WRONG 
Yes, Australian cricket was dominant at that time, mostly due to Bradman. Bradman’s career was interrupted by WW2, but the postwar team, with him as captain and best batsman, was known as the Invincibles. In 1948, they played 34 matches against the 2nd best cricket team in the world, and lost none.
[quote=“ISiddiqui, post:31, topic:932421, full:true”]
… and Gretzky and Dryden, who aren’t American
Since I’m [quote=“ISiddiqui, post:31, topic:932421”]
Nah… Pele, Maradona, Di Stefano, Puskas, Messi, C. Ronaldo… amateurs
[/quote]
/me Notices the nationality of half that list… tries to resist chauvinistic impulses… (fails)
We are now hereby friends for life. 
You mean like… two of the people I named?
Someone the other day was arguing with me that Mario Lemiuex (note to @penultima_thule - not American) was greater than Gretzky.
Game for game, there is an argument Lemieux was at least as great, just as there is for Bobby Orr. The thing is, staying in the lineup matters. Game for game, Patrick Mahomes is just as great as Brady, even in terms of winning championships; he wins one Super Bowl for every three seasons he’s a full time player, just like Brady. But it’s obviously silly to ignore that doing it for 21 years is different from doing it for 3. Like it or not, any discussion of “Greatest ever” must consider how long the player did it for. It’s a key consideration.
The fundamental premise of the OP in that the only team sports in the world, indeed throughout history comprise NFL, NBA, MLB or NHL.
That a couple of Canadians, or Mexicans, or Cubans had handy careers within the American professional ranks seems a lesser oversight.
Yeah, Lemiuex had problems with his back throughout his career, right? I think he would have done 50 in 50 had he stayed healthy, or something to that effect. I agree with you, though.
ETA: He did to it, and also did it another time, for his first fifty games, but he was sidelined with injuries for some of that season, so it wasn’t the first fifty games for the Pens. Illustrates your point, I think.
Just looking at the two athletes (and sports) in the OP:
On the one hand, if you took Michael Jordan, by himself, and put him on a court against a full high school team, he’d mop the floor with them. No football player can ever pull that off, because the way the sport works is just so different.
On the other hand, though, most high-end professional basketball players could pull off that stunt. Jordan being able to do it isn’t anything special. And it’s not even cut and dried that Jordan is the best at his own sport: Others have already named multiple other contenders.
But at this point, I don’t think anyone can realistically say that Brady isn’t the best football player of all time. He can’t win by himself, because football doesn’t work that way, but he’s still far and away beyond anyone else in his sport.
If there’s competition for this title, then it has to be among those who are unambiguously the best in their sport. In any sport where there’s dispute over who’s the best, none of them can be the most dominant athlete, by virtue of having that competition.