In 1942, music in America stopped. It had nothing to do with World War II, either. It was a strike.
The head of the American Federation of Musicians, James Petrillo, ordered all members to stop making any kind of music in response to a growing threat from new technology. Movies with sound had wiped out jobs of cinema piano players. Radio stations were playing records instead of exclusively hiring musicians to perform live. Jukeboxes made recorded music available on-demand in bars and restaurants across the continent, threatening the viability of live gigs.
For two years, union members were forbidden to enter a recording studio until the question of royalties was worked out. The only new music Americans heard during that time was material important from Europe and, strangely, acapella versions of songs because the strike action didn’t include singers.
Why? Because they weren’t considered actual musicians. More next time.