A few weeks ago, director Quentin Tarantino angered the Marvel corner of the internet by saying that MCU actors are "not movie stars." Quite honestly, I have to disagree.
While I understand his explanation that it's the "franchise characters that become a star," I'd have to argue that those franchise characters are often played by actors who've already proven that they're "movie stars" by earning some pretty prestigious awards and nominations. Others go on to earn similar accolades after their careers have been boosted by their MCU roles.
It extends beyond just the main cast, too. Marvel movies attract longtime, highly celebrated movie stars to supporting roles all the time.