Which makes it a bit baffling, because surely Francis Ford Coppola can attest to the art of adapting another pre-existing work into a movie.
Whether Coppola recognizes it or not is moot, the MCU and the process of creating it is art.
The difference between the two is Marvel is adapting more than the novels of Mario Puzo; it’s working with the collective visions of decades of authors and crafting stories for characters that ultimately go on to be used by other directors in a massive collaboration that takes extensive planning.