As an interesting side note to this discussion, last night at the Grammys, the winner for Best Heavy Metal song was (drumroll please) "Whisky in the Jar" by Metallica.
Between this, and several local bands running their own versions of "traditional music" including Gaelic Storm, the "folk band" from the movie Titanic, and other locals with roots from traditional Irish through renaissance drinking songs, there's a good scene still running.
I get the feeling that what will happen will be what's happened over the centuries. Most of the music, literature and other entertainment media will be forgotten, leaving a selection that will be carried on by future generations.
The future's in good hands... and if it isn't, well, it's a bit late to worry about it.