When Apple Music, Spotify and Tidal launched, they were hailed as digital prophets that promised new ways to monetize the experience. Thus far, their solutions have fallen short of fireworks. Just slightly over a quarter of Spotify's 75 million active users actually pay for the service. And, as The Guardian UK reports, despite pulling in €1.08 bn in revenue, its losses were €162.3m. So why are all these promising platforms sinking?