While Robert Downey Jr. has been an iconic actor as Tony Stark, it is said that "Iron Man 4" will push through without the eccentric playboy philanthropist in the lead.

While it remains unconfirmed, speculations suggest that a pay hike may be the culprit. Downey's net worth is upwards of $240 million, and as part of what can inarguably be said as one of the industry's biggest franchise, Downey Jr. is reportedly asking for an increase for "Iron Man 4." However, the management for the Marvel Cinematic Universe, itself lukewarm to continuing past the original "Iron Man" trilogy, is looking for fresh ideas. One rumored plot for the upcoming movie is a "somewhat reboot" of the franchise, with a female lead for the suit of armor – the so-called Iron Heart – as the main protagonist.

It is still unclear on what the story for the movie will be, though a female lead is possible. Should this happen, the movie installment will similarly mirror the events in the original comics. In Marvel Comics, the torch has now been passed down to Riri Williams, a girl who managed to reverse-engineer the iron suit based on Tony Stark's old technology.

Another rumor on the cause of the story shift is Downey's contract. Although the actor has expressed openly his interest to do another "Iron Man" film, his current contract has already expired and still awaiting renewal. However, it can be expected that a new contract will push through, given that Downey is said to appear briefly in the upcoming new "Spiderman" movie.

Downey donned the iron suit in the first "Iron Man" trilogy, and has also expanded to the "The Avengers" and "Captain America" films. He is expected to reprise his role as Iron Man for the next "The Avengers" installment, the two-part movie "Infinity Wars."