That's probably it
If I'm going to be at my computer I'll be listening to my own music files, but that's a very attractive offer, especially for the teenagers just getting into music. Remember having nagging discography gaps and having a limited budget, and only being able to listen to what was in your physical collection? Kids today can listen to basically anything they want, whenever they want. I know that's not at all a new observation but it just struck me. Will the youth have pet favorite albums? Will anything replace the excitement of goibg to the record store or waiting by the mailbox for a HAUL, and going through it one by one? As with porn streaming and the WWE Network, I can't imagine having such vastness of riches. Damn.
I do wonder why free Spotify on the phone is so different from what's on your computer. It can't be a copyright thing because streaming audio is a thousand times easier to pirate. Maybe to encourage you to sign up for premium.