Why didn't Tobey Maguire, Andrew Garfield's Spider-Men know of the Avengers? MCU theory explains
Spoilers for Spider-Man: No Way Home ahead:
In what was perhaps one of the most amusing scenes in Jon Watts' Spider-Man: No Way Home, Tom Holland's Spider-Man tells his senior Spider-Men, Tobey Maguire and Andrew Garfield, that he does have some experience working with a team and how he once fought alongside the Avengers. "I don't want to brag, but I will: I was in the Avengers," he says. But Tobey asks him, "The Avengers? That's great! What is that?" "Wait, you don't have the Avengers?" Tom asks. "Is that a band? Are you in a band?" asks Andrew.
This proved that even in the years that have passed in Tobey and Andrew's timelines, the Avengers have still not assembled in their universes. Which seems quite disappointing. However, a theory published on The Direct explains how all might not be lost.
The theory takes into consideration multiple Avengers and tries to establish if their existence in the previous two Spider-Man universes could actually be impossible. The biggest clue was added in by director Sam Raimi himself with 2004's Spider-Man 2. In it, JK Simmons is trying to come up with a name for Alfred Molina's freshly minted villain, when he discards ‘Doctor Strange’ as already taken and settles in on Doctor Octopus.
The theory called it ‘nothing but a fun Easter egg for fans at the time’, but after the events of Spider-Man: No Way Home, Dr Strange maybe more involved in Tobey's timeline than previously thought, however, ‘operating from the shadows.’
As for Natasha Romanoff and Clint Barton, staying in the shadows may not have been all that difficult either, considering how that was what they did before the battle of New York. Thor, as hinted in an episode of What If? that showed his life without Loki, would not have found a reason to visit Earth at all. Steve Rogers/Captain America, thawed out of the ice in 2011, three years after Spider-Man 3, might not have wanted to join back the workforce after the resurrection. Iron Man/Tony Stark maybe living the good life in Malibu and Dr Banner/Hulk never had an issue with being away from the limelight anyway.
As for Andrew's universe, there were reportedly talks of merging the two worlds together ever so slightly with The Avengers. The producers wanted to include the Oscorp Tower in the Manhattan skyline of the movie, but they got a bit late before the project was finalised.
The theory also suggests that while Tobey and Andrew's worlds may not have their own Avengers right now, they might get it in the future. One logic is that Dr Strange saw 14 million versions of the fight against Thanos and the Avengers win in only one. It's unlikely that Avengers did not exist in any of those 14 million timelines, otherwise why would Strange bother to sift through them.
Any which way, if Marvel does decide to bring Andrew Garfield into the Avengers, we already know that he is more than eager to play Spider-Man once again.