The Russo brothers respond to a fake quote circulating online about always knowing they'd kill Iron Man in Avengers: Endgame by joking that the original plan was to kill him in Captain America: Civil War. Anthony and Joe Russo joined the Marvel Cinematic Universe with 2014's Captain America: The Winter Soldier, and it wasn't long before Marvel Studios put them in charge of their biggest properties.
Many view Civil War more as Avengers 2.5 than the third Captain America film, and it proved to be the Russos' last stepping stone to directing an actual Avengers film. They directed Avengers: Infinity War and Avengers: Endgame, and have spent almost all their time for the last half-decade in the MCU. They're responsible for redefining Captain America in the 21st century, breaking up the Avengers, and killing several heroes along the way. The most notable of them all is Iron Man, because of not only his status in the MCU but also the circumstances surrounding his death.
Tony Stark snapping his fingers to wipe out Thanos' army was a heartbreaking, but satisfying, end to his journey. While some have questioned if this was the best way and the right time for Iron Man to leave the MCU, that's the decision the Russos made. They've been asked countless times about their thought process behind it, to the point where a fake quote from them started to circulate online. The quote claimed that Joe Russo knew Iron Man had to die back when he saw The Avengers for the first time, but also that he doesn't even like him as a character. The Russos debunked this quote on Twitter after it started trending, and jokingly said they wanted to kill him off back in Civil War.
The Russos have been very open about all the different versions of their stories they thought about, but they've never mentioned wanting Iron Man to die in Civil War. They have said they considered killing Captain America in the movie, just as he died at the end of the comic story. The comic precedent is why many expected Tony to die in Civil War though, as it would flip the comic and surprise audiences. But, that doesn't appear to be something they ever actually considered while developing the film. While this comment does seem to be made in jest, the joke does present a wild hypothetical where Iron Man is absent from almost all of Phase 3 of the MCU.
Since he's such a significant character in the franchise, Tony's absence after Captain America: Civil War would've completely changed what came after. For starters, either Captain America or Bucky could've been responsible for the death, making them murderers and fugitives. Spider-Man would then be without Iron Man's help and protection, while all of Earth would be without its biggest hero. This would leave someone like Doctor Strange to take on the responsibility. Furthermore, it would spell doom for the entire universe, as Tony wouldn't have been able to solve time travel and defeat Thanos with a snap of his own. Luckily for fans and the characters in the MCU, Iron Man did stick around through Avengers: Endgame to save the day.
Source: Russo Brothers
