We already know that the Multiverse exists, thanks to Doctor Strange. But why wasn't it even explored in Avengers: Endgame? The film's writers had a compelling reason why the whole idea was avoided in the Marvel Cinematic Universe flick.
Christopher Markus and Stephen McFeely recently made an appearance at the San Diego Comic-Con where they confirmed that the Multiverse is out there but it had to be ignored in Endgame (via Comicbook.com).
"It clearly exists because Doctor Strange has talked all about it, that's part of the fabric of that," McFeely said. He then explained that he somehow disagrees with Marvel and Marvel Studios president Kevin Feige in terms of the direction that the MCU is taking. After all, it was important for fans to understand that Tony Stark and Natasha Romanoff can never be replaced.
Markus added that this was especially important in Endgame.
Perhaps things will change in Doctor Strange in the Multiverse of Madness where we could see Tony or Nat returning. On the other hand, Endgame already gave both characters a certain closure.
Doctor Strange in the Multiverse of Madness is scheduled for release on May 7, 2021.
Related: Marvel Superfan Has Watched Avengers: Endgame An Amazing 200 Times And Refuses To Stop