It doesn’t matter because it would average out because you will have queen fans who listen at a high amount as well. Unless for some reason an artist has a fan base which majority listen to less music than the average person for some reason.
Although, you seem to make a good point. BMI differentiates radio royalties by number of performances[1]. Except---and I haven't researched this very well---they seem to pay more if a song is more popular.
Then surely the solution must be to try and determine which artist actually brought in the users and give them some kind of lead bonus. I would assume any platform that started doing that would eventually beat platforms that didn't because all the lead generating bands would move there and no new users would have a reason to go to the other services.
It will give you a high probability of being near right in a random case but completely destroys the detail. In this case the detail is niche music genres and artists, growing or dying, that contribute greatly to the "flavour and future of society". When we assume too much here we actively suppress minority positions making certain genres and use cases completely non-viable.
I highly doubt elevator music has the audience listening profile of eminem, and thus the current system either over or under pays elevator music producers.
Other areas which are likely extreme are: new EDM artists, classical compositions, play-a-long songs (ie learn guitar), cultural artists (US christian youth, Belarusian native rock).