There is a certain amount of unreality in all movies (they're better organized than real life, for one thing), but movie musicals are more unreal than most.
Descended from opera and operetta, musicals invite us into a world where people don't just talk about their lives, they sing about it. Sing and dance! Pickpockets in 19th Century London, street gangs in 1960s New York City, Navy nurses in World War II, all elaborately choreographed as they sing about their triumphs or trials.
And audiences love it. Some of the most popular movies of all time have been musicals: The Sound of Music. My Fair Lady. South Pacific, Oklahoma, Singing in the Rain and Fiddler on the Roof are some that have withstood the test of time. These multiple award winners and box office champs sang their way into our hearts.
Musicals arrived in movies with the advent of sound. The big name in early music-laden films was director Busby Berkeley. His signature style was to create a movie about show business, and the songs were huge staged set-pieces with scores of elaborately costumed women weaving complicated patterns filmed from a height. The visual effect was dazzling, the music mostly forgettable.
The heyday of this genre was the 1950s and 1960s, with the songs incorporated into the lives of ordinary people going about their lives, tutoring children, picking pockets, fighting a world war. Most of these films began on the Broadway stage, and the big names were Rogers and Hammerstein, and Lerner and Lowe. These famous music and lyrics teams put the music front and center, with songs that both fit into the context of the plot and yet possessed a universal quality that made many of the songs hits and standards in their own right.
Recent decades have been unkind to movie musicals although there have been a few exceptions. 1971's Charlie and the Chocolate Factory has been an enduring hit. While Andrew Lloyd Weber's musicals have been long-running hits on Broadway, their translation to movies has been less successful.
It's uncertain why the genre has fallen out of favor in recent years. Perhaps the world is simply waiting for the next Rogers and Hammerstein.