Theaters & Musicians:

h/t @reiver

Dror Poleg (Twitter): When films were silent, theatres employed local musicians to accompany each screening. But once films gained a soundtrack, local musicians were no longer necessary. The economic implications were significant: In 1927, around 24,000 musicians were employed in theatres across the US and Canada. But then came the first talking film — The Jazz Singer.
By 1930, some 7,200 musicians lost their jobs — 30% of the pre-talkie total. In some markets, such as New York and Cincinnati, musician unemployment reached 50-75%.
Over time, all theatre musicians were eliminated, and recorded soundtracks became par for the course. The advent of records, radio, and talking films made creative work scalable: "300 musicians in Hollywood supply all the 'music' offered in thousands of theatres. Can such a tiny reservoir of talent nurture artistic progress?"