Many music lovers subscribe to Spotify which has 30+ million tracks to choose from. However, it doesn't have the Taylor Swift albums because she pulled them. If those customers want to hear Taylor Swift, they have to buy them from Apple Itunes or Amazon Music.
T Swift made a voluntary choice to net her the best paying deal which means digital music customers have to pay for more than one service. Add up thousands of different musicians each looking after their self-interests for the best deal and it ends up creating several intermediaries.
> Customers who want to watch Utopia can pay money just to watch Utopia, without having to sign up for HBO.
It's not about being a monthly subscriber or an on-demand occasional payer -- it's about the mystery of HBO even existing as an intermediary that often puzzles techies.
