Not so much the MCU, as a concept, but the actors portraying the roles, as they come and go in the future. ...Example: .Even though Spider Man wasn't in the MCU, imagine if Universal had used ride film with Toby McGuire in the role, that would be really really outdated. And then if they spent the money to update to his successor in the Fox films, that too would have been already outdated. And so on, and so on.....Now, they only need to update when they want better film quality as technology advances.