And it's not like Marvel movies invented recasting. How many different actors have played Felix Leiter in the Bond movies? Johnny Weismuller had at least two different Janes in the old Tarzan flicks. Dr. Frankenstein's fiance went from being a blonde Mae Clarke in the original movie to being a brunette Valerie Hobson in BRIDE. Professor Moriarity was played by at least two different actors in the old Rathbone/Bruce "Sherlock Holmes" movies. And let's not forget Catwoman and the Riddler and Mr. Freeze in the original Batman tv series . . ..
The point being that recasting is like the sun rising in the east. It's always happened and it's always going to happen.
(And, yes, I watch too much TCM.)