LOS ANGELES (AP) — Apple’s $3 billion purchase of headphone maker and streaming music company Beats Electronics sheds light on a rarely recognized reality in the music-streaming industry: It’s hard to succeed in the business without offering other products and services.

Streaming-music companies like Beats Music, which charge users up to $10 a month, can sometimes pay as much as 70 percent of their revenue in artist royalty fees. That leaves little left for advertising and promotional campaigns to explain to consumers the benefits of paying for a music service.