There's just one problem with your model. There's no royalty difference between a Spotify subscriber playing one song vs 1000 songs if it's just % of subscriber's listening time. Someone who gets more plays by absolute numbers is going to be upset when they don't get a proportionate amount of money. The only way to make more money on Spotify is to get more fans and/or convince your existing fans to listen to fewer artists.

This is a popular HN suggestion for disbursement but it makes the math super weird.