> Why wasn't this material protected in, at least, a fireproof area, or, better, in some salt cave in the Utah desert?
Because they don't actually care. No one in their right mind in these companies will sign off on releasing this stuff to somebody else. If some performance just happens to include someone famous and becomes worth any reasonable amount of money, the person who signed off will get fired.
The best way to preserve this stuff is to make copyright expire after 10-20 years. That way these companies can't just sit on these things indefinitely. They'll have to monetize it or someone else will likely come along and monetize it.
You don't have any idea how the music business actually works then. The sound recording copyright allows the owner of the master recording to generates revenue from "master use license fees." This is the permission to use the actual recorded version of the song in movies and television. When Martin Scorsese wants to use a Stones song in his movie, he must pay the "master use license fee" to the record company. These companies care a a lot about those fees and the masters that enabled them. I can assure you. The tragedy of this is more the result of two decades of mergers and consolidations of record companies whose headquarter are all in Los Angeles.
>"The best way to preserve this stuff is to make copyright expire after 10-20 years"
That's not actually how it works. The master recording copyright follows the physical media not the owner. What you are suggesting would actually hurt the artist. More especially so at a time when their recording was becoming a "classic."
> In that case, they’d just shred the masters unless someone offered to buy them for enough — and for most stuff, no-one would.
Unlikely. Shredding costs time and money that no one will allocate.
Suddenly you have: "Well, these things are about to come off copyright, so if we don't get money now, we're never going to get any at all." So, someone looking to add a few bucks to his bottom line budget in the company will almost certainly toss them out at a reasonable price.
Contrast to now where the risk is that you sell off "Random Garbage 42" for $10,000 that happens to have a 10 second cameo of Elvis in it, and it becomes worth $250,000.
Because they don't actually care. No one in their right mind in these companies will sign off on releasing this stuff to somebody else. If some performance just happens to include someone famous and becomes worth any reasonable amount of money, the person who signed off will get fired.
The best way to preserve this stuff is to make copyright expire after 10-20 years. That way these companies can't just sit on these things indefinitely. They'll have to monetize it or someone else will likely come along and monetize it.