Why Don't Some Musicals Transfer Well
Some great Broadway shows don't transfer well to the big screen. For example, the most popular Broadway show of all time - Guys and Dolls - did not make for a great movie. One of my favorite Broadway shows is Brigadoon but the movies was a dud. Another example is this movie - Camelot.
I maintain that the reason is that the stars of the movies are not singers. Guys and Dolls featured Marlon Brando and Jean Simmons. Brigadoon was ruined by Gene Kelly and Camelot did not fare well because of Richard Harris and Vanessa Redgrave.
My Fair Lady, although winning an Oscar for best picture, still came under a lot of criticism for dubbing Audrey Hepburn's voice.