How do you know there isn't any actor out there who has Robert's talent and charisma? How do you know there isn't any actor out there who could do justice to the role of Tony Stark or make the future Iron Man movies successful? Based on what? How would you know if you don't see any new Iron Man movie with a new lead actor?
Don't you think it is time Robert took roles that are of his acting level? He is wasting his talent on these Marvel pop corn flicks.