[Glyptodon]

You're the one expressing a non-sequitur. Proportionality of royalty should enable other services to compete with Pandora on the same playing field, so profit would also be proportional to decreased costs or Pandora would risk being wiped out by competition. There'd be no ability for collusive cartels of copyright holders to act as market deciders, or for single players to succeed at profiting disproportionately with respect to their costs.

I guess maybe this would require a corollary of compulsory licensing, but I'm pretty sure that already exists to a large extent.