Marvel considered Robert Downey Jr. for Doctor Doom, but he saved the MCU instead

polygon.com:

In the grand tradition of Marvel’s What If?, consider this: Instead of headlining 2008’s Iron Man, Marvel Studios’ first self-financed “Marvel Cinematic Universe” movie, Robert Downey Jr. secures his place in comic book movie history by taking on the role of Doctor Doom in 2005’s Fantastic Four. According to Jon Favreau, it could have happened.

In a new retrospective celebrating the 15th anniversary of Iron Man, Favreau — who not only directed the film but played Happy Hogan alongside Downey Jr. and throughout the MCU — sat down with Marvel Studios president Kevin Feige to look back at the movie that started the unstoppable entertainment machine. Favreau’s penchant for mixing comedy and drama, and the “latitude” he gave Downey Jr. when ad-libbing over the screenplay, wasn’t just a way of being “very consistent with Stan Lee’s tone,” as the director puts it, but the way Marvel broke out from the early 2000s Marvel movies and the grim tone of The Dark Knight, which would arrive later that year. Iron Man wasn’t just a movie it was a primordial soup.

“That tone you and Robert discovered on that movie became the template for what the MCU became,” Feige admits, with a look on his face that suggests it all could have gone very wrong. Casting Downey Jr. created his empire. “On later movies […] there were dark days,” the producer went on to say, “and I would say to Robert, ‘We wouldn’t be in this mess if it wasn’t for you.’ Meaning, we wouldn’t have a studio if it wasn’t for him.”

And as Favreau reminds Feige, it was possible Downey Jr. may have been out of contention for the role if Marvel, then spearheaded by Feige’s mentor Avi Arad, had plugged him into a different vehicle. The only reason Downey Jr. came in for a general read