I explained in an earlier article ways Spotify can earn artists more money, and the above statements support that claim.
You'd have to understand something about advertisers to understand my train of thought. They flock to where the people are. Think about the way you advertise your music?
You flock to where the people are. You go on Twitter, SoundCloud, and YouTube because people are already there! They have a customer base that you're trying to turn into your fans.
All you're doing is borrowing traffic off someone else. Why? Because it's a low barrier to entry and it's free.
Spotify has the same model.
I've heard one too many people say about music, "Why would I pay for something when I can get it for free?" Before, there was a morality complex (for those aware of morals) that they shouldn't steal music, just as they shouldn't steal movies.
With services like Spotify and Netflix, that excuse is off the table! People have widely shown they're willing to pay small monthly fees for unlimited access to music and movies.