The subject of preserving recordings permanently has come up on Mudcat before. One of the insights I remember gaining from the thread was that to preserve a digital archive you do have to keep copying it as media technology changes, but as the digital copy can be perfect that doesn't matter (other than the incovenience of having to do it). There's no special digital medium that's guaranteed to be be readable in 100 years time.

This contrasts with paper records (i.e. books, not sound of course) which last for centuries if kept properly.

Anahata