100 Years from now, popular music will just be a series of grunts, and rock music will be something you read about in an encyclopedia.
Classical music, however, will live forever.
Rock has passed the 50 year mark and is showing some staying power, although it is dwindling because today's artists stink so badly.
I suspect it may take 200 years before rock is a fossil. I just wish rap would die like disco did.