A subscription-based music service for Guitar Hero and other titles could be a possibility.
Guitar Hero Founder Wants Subscription DLC : Read more
Guitar Hero Founder Wants Subscription DLC : Read more
No, he's just worried that PC modders will make the DLC redundant a-la Stepmania.His comment also ties in to an answer regarding the non-existent PC version, declaring that licensing is the biggest issue thus far in regards to allowing gamers to access their music through the various games.