Avengers: Endgame was a turning point for the MCU. It was the end of an era, both because it signaled the beginning of Marvel Phase 4, and because it was the end of the road for a few beloved characters. Some of us are still coming to terms with the fact that we’ve seen the last of Tony Stark. But Endgame’s writers, at the very least, have offered an explanation for why they chose to write his death into the series, and why that was better than letting him live to see Iron Man 4.
Whether you like all of the 24 movies or not, the capital that Marvel built up allowed them to do things like make a movie starring a raccoon and a tree, right? You would’ve already had Iron Man 4 if it was any other studio. But they decided, 'No, we’re going to take chances on all these other things.' To put a flag in the ground and say, We’re going to end something and take characters off the table, is, I think, kind of daring, but selfishly it was really great for us.
According to Stephen McFeely and Christopher Markus, MCU’s creative team planned the demise of Tony Stark years before Avengers: Endgame. Christopher Markus said they knew that when they raised the stakes high enough, it was important to follow through. They could've just taken the easy way out and let Tony continue with Iron Man 4 but fans wouldn't respect the choice.
It needs an end or it loses meaning. The end is what cements the thing, to actually sew it together and bring it to a crescendo, and yeah, take people off the board, finish their arcs. If Tony made it out the other side, and Iron Man 4 was waiting there, you’d be like, [shakes head] One too many…
Iron Man 4 would likely have been another blockbuster win for the MCU. So, it was daring for them to recognize the narrative importance of wrapping up Tony Stark’s storyline in a satisfying way, even if it meant taking one of their most popular characters out of play. And though some fans may not agree with all the creative choices made in Avengers: Endgame where other characters’ exits are concerned, we can give credit where credit is due here -- Iron Man’s exit was truly epic.