In the first half of the 20th century, James Caesar Petrillo of the American Federation of Musicians saw that recorded music, and the broadcasting of that music on radio and jukeboxes, was a threat to his boys' jobs (and his).

Those powers are right to be disturbed. They tend to become entrenched in selling music in particular manners and styles and systems. New technologies inevitably shake all those things up.

There are probably fewer professional live musicians than there would be if we had never enjoyed radios, jukeboxes, transistorized stereos, or computerized file sharing. Yet with every change, people's access to better reproduced, more portable, more personalized music grows.