One of Disney's rules seems to be no sad endings. If they did a movie about OTMA, perhaps they would alter the original story completely to give it a happy ending, the way they did for Hunchback of Notre Dame, or, to cite a non-Disney example, the way Delta Force is a fictionalized account of TWA Flight 847, but portrayed as ending with an Entebbe-inspired rescue, rather than with the terrorists' demands being met, as happened in real life.