Most recently there has been an array of speculation surrounding the future of Chris Evans in the Marvel Cinematic Universe, but now the Captain America actor has really thrown the cat amongst the pigeons by suggesting that Robert Downey Jr. is much closer to quitting as Iron Man than he is. Chris Evans recently crushed the spirit of millions of Marvel fans when he candidly admitted:
Downey is far closer to reaching that point where he may walk away. And I don't know how you replace Downey as Tony Stark. I don't know who else can touch that.
Since Robert Downey Jr. made his debut as Iron Man and kicked off the Marvel Cinematic Universe all the way back in 2008, it would make sense if the Oscar-nominated actor now decided that the time was right for him to bid farewell to the character. Especially because Downey is reprising his role as Tony Stark/Iron Man in a number of films in the very near future, which would help to soften the blow if he did bow out.
Not only does Tony Stark have a prominent part in Spider-Man: Homecoming, which seemingly sees Robert Downey Jr. playing a mentor figure to Tom Holland's burgeoning superhero, but after the events of Captain America: Civil War, he'll also get to awkwardly meet up with the rest of the Avengers again in Infinity War and the still-untitled Avengers 4. Once Downey's work on these films is complete, though, he's not actually contractually obliged to return as Iron Man, which means the decision rests with him.
Chris Evans' additional remarks to USA Today are spot on, too, because trying to find a replacement for Robert Downey Jr. as Tony Stark is virtually impossible. Not only did his casting and performance in Iron Man immediately pin down the Marvel Cinematic Universe's playful tone, but it brought a charisma to the series that it was able to build and play off of. With that in mind, I believe that Marvel shouldn't and won't look to replace Downey as Iron Man in the near future.
In fact, I believe that Spider-Man: Homecoming will set Tony Stark up as an aging superhero that's little past his prime, something that was teased at Civil War. Then, in the Avengers: Infinity War films, Tony Stark will prove himself and have a triumphant farewell, while paving the way for a new younger superhero to take the reigns of the Marvel Cinematic Universe. That could involve him saving the day and moving off into the sunset, or it might involve Marvel finally killing off someone of importance. I think it will probably be the former, because that would leave the opportunity for the Marvel Cinematic Universe to turn to Downey in a supporting role if they ever actually hit some trouble.
Either way, we'll get a better indication of Robert Downey Jr's Marvel future after Spider-Man: Homecoming is released on July 7, an even clearer idea after Avengers: Infinity War hits on May 4, 2018 and then everything should be apparent when Avengers 4 arrives on May 3, 2019. Which means that we still have at least two years worth of Downey to look forward to.