All the elementary schools I ever went to, back into the late 50s, had a music teacher. Not all teachers (Or anyone else, including bitchy, demanding parents) can read music or understand a damned thing about it, probably even fewer now than back then. In those days, a lot of people knew how to play some instrument, now all most people can play is an MP3 player.
A lot of the same is true of art, though not all the schools had an instructor for that until what is now called middle school. My sister teaches art for a large consolidated school, mostly elementary, works her ass off at it, and drives a beater. You couldn't pay me enough to put up with the bullshit she gets from her manipulative, backstabbing, and conniving administration, the shitheads on the school board, loony Leftist parents who think their brain-damaged offspring are just misunderstood and who 'Know more about primary education' than any teacher their little hellion has ever had, and the equally-loony Right-wing parents who think education should be limited to Scripture and cipherin'.