Check out the movie "The Wrecking Crew". It's about studio musicians fixing, rewriting, playing, and singing the music created by the "bands" you've all heard of, so the albums were good.

Then, the bands belatedly had to learn how to sing and play in order to go on tour.

I think about The Wrecking Crew whenever I hear the sob stories about bands being underpaid and the producers reaping the lion's share of the profits.