Ask how digital recording alters the sounds of artist today and how/if it could've helped performers that used the older formats. Also ask if its easier for artist to get their names/music out there to more people thanks to the internet via facebook, twitter, myspace, youtube, etc.
There are very many questions that you can ask on how the music industry has changed. You can ask about the influence of advanced technology to their music. You can also ask them to compare how music was to what it has become now.