This problem has not only cultural but also commercial ramifications: "'If people can't figure out why a song isn't on Guitar Hero, there's a good chance it's because there's no way to revive the digital master file,' says one industry source." Deluxe reissues, soundtrack and video licensing, and other forms of reuse and repurposing -- all of which account for a substantial percentage of record label profits -- are all dependent upon the existence of multitrack masters; the files on CD's and backup tapes simply won't suffice.
The article is better at describing the problem than outlining the possible solutions, but it's a thought-provoking piece nonetheless. It also cites a recent Council on Library and Information Resources-Library of Congress report focusing on the challenges of preserving analog and, in particular, digital audio recordings -- which is essential reading for archivists working with audio materials and of interest and use to archivists and librarians working with other types of digital materials.
. . . And if reading about these problems makes you start thinking about the fate of your own digital music files, Rolling Stone has also posted five helpful preservation tips. I'm not wild about tip no. 2 -- "audiophile-quality files" can be a preservation nightmare if encoded in proprietary formats -- or tip no. 5 -- I suspect that at least a few cloud-based file hosting services will bite the dust with little warning -- but the other three tips are superb. Tip no. 1, "Back it up, stupid," is particularly important. Put copies of your music files (and your other important files) on a portable hard drive, and then store that hard drive well away from your computer so that the chances of losing both copies to fire, burst pipes, etc., is minimized; better yet, keep the portable drive at your office, a relative or friend's house (you can keep his or her backup drive in exchange), or in a safe deposit box.