In the early days of the Marvel Cinematic Universe, one of the things that made the operations of Marvel Studios stand out compared to other budding franchises was the long-term contracts that were signed by actors. It was viewed as important from jump street for the brand to lock in stars whose repeat appearances would solidify the expansive world building plans, and so deals were negotiated that saw performers sign on to play their respective characters in not just one or two movies, but instead at least six (some, like Samuel L. Jackson and Sebastian Stan, got nine-picture deals). With individual leads like Robert Downey Jr., Chris Evans, and Chris Hemsworth respectively locked in to star in both solo trilogies and an Avengers trilogy, grand design was able to come together, and the door was left open for the MCU to become what it is today.
