In 2008, Marvel took a gamble. They hired Robert Downey Jr. a man whose career was genuinely believed to be over due to addiction issues and they gave him a flagship role in the nascent "Marvel Cinematic Universe (MCU)". Jon Favreau, Director of 2008's Iron Man, insisted that only Downey could truly play the part of Tony Stark. After a lot of intense debate, Marvel agreed.
The "Iron Man" trilogy is among the most popular movies in the "Marvel Cinematic Universe (MCU)," and he brings enough star-power to command a staggering salary for his appearance in Captain America: Civil War.
Robert Downey's Tony Stark was to be replaced by Riri Williams, a teenage girl. Of course, comic book fans will know that Riri Williams is just the latest in Marvel's famous line of "Legacy Heroes"; the teenage character has been introduced over in the comics, and has indeed taken over the role of Iron Man, changing the name to "Iron Heart." Sources reported that Iron Man 4 is now scheduled for 2019, and that Downey no longer feels like the roles for him.
"Robert thinks that his time of donning the suit is up and that a younger person should take over from him. Superhero movies are for the youngsters. Hence, it would be unfair for an older person to carry on after three successful titles," as stated by Master Herald.
The Iron Man franchise is tremendously popular, and Marvel's Phase 3 slate does indeed include as-yet-untitled films scheduled for 2019. Last November Kevin Feige was asked about the possibility of replacing either Robert Downey or Chris Evans.
"Luckily we don't have to make that decision anytime soon. There are a lot of movies that everyone is signed on for, and we get to enjoy them for a long time. Robert Downey Jr. is Iron Man, and right now I can't envision anyone else," as stated by the actor Kevin Fiege.