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Why Did Disney Cartoons Become Broadway Musicals?
Ben Gilbert and David Rosenthal say Jeffrey Katzenberg turned Disney cartoons into Broadway musicals that happened to be animated, and that switch made the Disney Renaissance. Snow White had catchy songs. Those films were not stage musicals, and they did not follow a musical's story shape.
Katzenberg recruited Howard Ashman, introduced by David Geffen. Ashman wanted animation because he saw a link to musical theater that others missed, and he brought composer Alan Menken. They had done Little Shop of Horrors together. Their first Disney film was The Little Mermaid.
Ashman's rule was the Broadway third song. The leading lady sits down and tells the audience what she wants, and the rest of the story is whether she gets it. In The Little Mermaid that song is Part of Your World. Ariel says she wants to go where the people are.