I'm guessing they don't do this voluntarily because they've seen how the music industry had its revenues eroded by Spotify/iTunes (where mostly the user can pick one and get pretty much everything). They're probably ignoring the fact that music piracy is presumably lower than ever because of this.
Additionally there must be 'big fish' within their market. People who spend $1,000s on consuming viewing entertainment and would go whatever the 'preferred/legal' way to do it was.
