$10 a month per user doesn't cut it. Spotify actually makes more money off free users than paying users, because the ad placement they achieve for free users is

$10 a month per user doesn't cut it. Spotify actually makes more money off free users than paying users, because the ad placement they achieve for free users is worth more than $10/month/user. In reality, it's their interest to keep the free user/paying user ratio to a certain zone, or they'd be losing too much money.