Iron Man 3 opened last weekend and has already raked in nearly $800 million worldwide but we may have seen the last of Robert Downey, Jr. as the eccentric billionaire superhero. That is, unless Marvel and Disney strike a deal to get have him reprise his role for a possible Iron Man 4 or Avengers 2. Unlike other superheros Downey has embodied the personality of Tony Stark in such a way that Kim and John say it's hard to imagine the studio replacing him. Still, Isaac Perlmutter, the head of Marvel which produces Iron Man and Avengers, is reportedly the kind of executive who feels stars are replaceable. Plus, Downey doesn't come cheap. According to a recent GQ profile, he earned $50 million from Avengers. Will the studio be willing to make a similarly rich deal to keep him in the fold? Robert Iger, CEO of the Walt Disney Company, which owns Marvel, may want to pay him what's necessary to keep these lucrative franchises going. Could Iger dip into his own wallet? After all, according to a recent article by David Carr in the New York Times, he makes a hefty multi-million dollar salary himself.