All six original Avengers could’ve died in Avengers: Endgame; it was an idea floated by the president of Marvel Studios.
After originally coming together in 2012, the Marvel Cinematic Universe brought the original Avengers together one last time in Endgame. As fate had it, all six original members — Iron Man (Robert Downey Jr.), Captain America (Chris Evans), Black Widow (Scarlett Johansson), Thor (Chris Hemsworth), Hulk (Mark Ruffalo), and Hawkeye (Jeremy Renner) — survived Thanos’ snap, and of course, they saved the day, bringing back everyone who vanished at the end of Avengers: Infinity War.
Per ScreenRant, although Endgame brought all of the original Avengers back together, it was widely believed that this would be the last time it happens. Indeed, Endgame killed a few of them; Black Widow was the first one to die, as she sacrificed herself on Vormir so the Avengers could obtain the Soul Stone. Next was Iron Man’s turn to go, when he used the Infinity Stones to wipe out Thanos’ army and save the world. And while Captain America didn’t die, it seems unlikely that the elderly Steve Rogers will return to super-heroics.
All of that hit fans hard, but Marvel Studios president Kevin Feige originally proposed that all of the original Avengers should die. That’s according to The Story of Marvel Studios: The Making of the Marvel Cinematic Universe. Directors Anthony and Joe Russo were against such a proposal, knowing that the movie wouldn’t be able to handle such a devastating loss of major characters and honoring them with a proper sendoff that wouldn’t leave viewers extremely upset.
Joe Russo said, “Kevin’s initial pitch was that it was Toy Story 3 – a ‘they’re all gonna jump into a furnace together’ concept.'”
Since Avengers: Endgame didn’t go through with this idea, it allowed the movie to make sure Iron Man’s death hit audiences harder and left room for Captain America to get his own happy ending. It also gives the MCU a chance to give the rest of the original Avengers a better sendoff whenever their time comes. Black Widow’s death was expanded on in this year’s Black Widow with Yelena Belova visiting Natasha Romanoff’s grave. That leaves Thor, Hulk, and Hawkeye to have their MCU stories wrapped up, with Clint Barton’s death theorized to come in Hawkeye. Mark Ruffalo’s Bruce Banner and/or Hulk is scheduled to appear in the upcoming She-Hulk series on Disney+, and Thor’s next movie is due out in the summer of 2022.