No, it might not have. It was an idea of Truman Capote to cast Marilyn Monroe in this movie, but the studio was against it because it thought that this movie would destroy Marilyn’s career. So the studio cast Audrey Hepburn which of course angered Capote who clearly wanted Marilyn for his role. To cast her, the studio hired Audrey’s designer Hubert de Givenchy to make outfits for her role. As the result, Audrey played her character better than Marilyn would ever do.
I’m feel sad for Marilyn that she was rejected by the studio to play role that was written for her but Audrey have done it a far better and made it with style and class. Can you imagine what the movie would look like if Marilyn would play its main role, not Audrey? Honestly, no disrespect to the devoted Marilyn fans but again sorry not sorry. As I said, if you want Marilyn Monroe in the Breakfast At Tiffany’s, read the book with the same name, but if you think Marilyn would play this role better than Audrey, think again. The only reason Breakfast At Tiffany’s is so popular is because of its main star Audrey Hepburn. Would that movie be so popular and loved if it was played by Marilyn, not Audrey? Think for yourself.