Aerosmith is still very much alive, and was even touring at one point. I don't think it's needs to change just yet. However, if one of the band members dies, I am curious to see what Disney will do. There aren't a ton of rock bands left that EVERYONE has heard or listened to. Possibly U2? Jonas Brothers is a terrible idea, as they are much more of a passing fad. The only other idea is to have a ficitioanl band, and have Disney pay royalities on cover songs. That way they could use any music they really like. Just sung from an unknown/ficitional artist.