Really? What about the anti-Spotify's like HypeMachine? Fiercely independent, trendspotting/trendsetting, and sustainable. It's a very valuable service to lots of folks.
IMO Spotify/Rdio/Pandora could only ever hope to go the advertising route over subscription because they couldn't crack the much harder distribution problem (e.g. the HypeM's, SoundCloud's, Drip's, etc).