The success of the "Iron Man" movies is undeniable in every aspect, but as fans wait for new updates on the fourth installment of the box office hit franchise, there are rumors suggesting that Robert Downey Jr. may not reprise his role due to budget constraints.

According to reports, Downey Jr. might no longer be seen as the great and powerful Tony Stark in "Iron Man 4" since some say Marvel can no longer support his salary claims and conditions. While the reports have not been addressed by the comic book and film giant, it isn't impossible that Marvel may be thinking twice in giving Downey Jr. the role for the fourth time. This is because the "Avengers" star is one of the highest paid actors in the industry.

MCU executives are allegedly no longer interested in spending tons of cash for a film that will feature Tony Stark, especially with the many other franchises that's also raking in a lot of money for the company.

While Downey Jr. has a good reason for having a rather expensive price tag, some experts believe that the actor may be too old for "Iron Man 4," especially since the role will need him to be physically fit and always ready for stunts that require him to be on-screen instead of using a double.

Meanwhile, ever since Marvel introduced 15-year-old Riri Williams to the comic book realm, there have been rampant rumors about the character possibly taking over the movie industry as well.

While Riri is apparently Tony's successor in the comic books, movies don't necessarily have to follow through with the books. On the other hand, with all the rumors surrounding Downey Jr.'s Tony, it wouldn't be surprising if Riri shows up in "Iron Man 4."

There are also some who believe that Downey Jr.'s Stark may be killed off in the first couple of minutes of the fourth movie, shortly after he passes down all of his knowledge to Riri. This is a more reasonable step that Marvel may want to take since Downey Jr. has established a reputation among fans and they likely won't accept some lousy Tony Stark death or departure in "Iron Man 4."