Avengers: Endgame is a major achievement. It manages to bring over a decade of Marvel Cinematic Universe storytelling full circle for the biggest superhero adventure that's ever been seen on the big screen. And while it's certainly not perfect and arguments can be made that the turns both Black Widow's and Captain America's stories took weren't the best ideas, Iron Man's journey in the film is another story altogether.
Robert Downey Jr. kicked off the MCU as Tony Stark in the first Iron Man movie, opening the door to a world of interconnected superhero stories the likes of which we've never seen. Through it all, Tony was the most human of the Avengers, based on what we were shown on-screen. Fans watched Tony battle PTSD and anxiety attacks after the Battle of New York in Iron Man 3 and face the reality of the death of his parents in Captain America: Civil War.
Then, in Endgame, viewers see the man Tony had become without the life of a superhero. It was peaceful, filled with the love of his family, and seemingly perfect. Yet still, after Thanos snapped away half of the universe, there was a mission for him and the reunited Avengers. When it came down to it, Tony was willing to sacrifice his own life to obtain the victory the team needed, giving him the ultimate superhero exit. He may have died in battle, but in doing so, he saved his family, his friends, and the rest of the universe.
For the most human of the Avengers team, this particular ending was exactly what the character Tony Stark--and the fans who watched him grow throughout the Infinity Saga--had earned.