With Marvel riding high with Captain America: The Winter Soldier and Guardians of the Galaxy as 2014's top two films, there has been less talk of a sequel to Iron Man 3. It's seemed that the plan is to build individual arcs for each character told as a trilogy, then spinning them into The Avengers while new solo movies emerge. With Doctor Strange and Ant-Man entering the cinematic universe in the next couple of years, there's little need for Robert Downey Jr. to suit up for anything outside of the Avengers ensemble, and now it seems even less likely that will happen.
In an interview with Variety while in Toronto promoting his film, The Judge, Downey Jr. basically said Iron Man 4 isn't happening....
RDJ: "There isn’t one in the pipe. No, there’s no plan for a fourth ‘Iron Man.'”
Downey may be Marvel's most popular star but he also knows his power only extends so far. When asked if he would let someone else play Iron Man, he said...
RDJ: "I like that the idea is that it would be up to me, like I’m casting director for Marvel."
Kevin Feige has said in the past he perceives Iron Man to be interchangeable like James Bond, so there's always that chance a move is made at some point. But the bigger point may be that Marvel could set this up without Downey's input or knowledge.
Iron Man will be seen next in Avengers: Age of Ultron on May 1st 2015.
