Cost of goods sold for an artist are fixed whether their song is streamed 100 times or 100 millions times. After that cost is recouped, it shouldn't matter much

Cost of goods sold for an artist are fixed whether their song is streamed 100 times or 100 millions times. After that cost is recouped, it shouldn't matter much what the rate paid to the artist per stream is. Why are we still clinging to this expectation that artists must be multimillionaires to be satisfied with their careers?