In earlier days, I hypothesized that fan preservations vs studio preservations followed the r/K selection theory.
While studios invest a huge amount of effort in preserving a small number of archival sources (like elephants having a small number of young, but investing a large amount of resources in raising and protecting them – K-strategy), fans simply try to distribute their preservations to the widest possible audience, in the hopes that some small percentage surviving through the years is sufficient to keep the preservation going (like rabbits having a large number of relatively vulnerable young, hoping that some of them live long enough to reproduce – r-strategy).
Basically, wide enough distribution, if sustained, is in itself a form of long-term archival. In this case, wide enough to cross national and legal boundaries to a degree that any of the current campaigns to legally suppress historical cultural artifacts like the Star Wars Trilogy can’t ever entirely succeed in completely wiping them out (predators can’t eat them all). That is, in part, why I do what I do – making fan preservations appealing outside the English-speaking world. And one advantage of the r-strategy is that adaptations can more easily be made on the fly (rapid evolution from fast generational turnover, like bacteria). If FLAC and DTS-MA fall into disuse, replaced by FutureTech audio, for example, we just transcode to the new format and the strategy continues. No need to document how to decode an obsolete audio format, we just stop using it.
And like r/K theory, nothing maps perfectly onto one strategy or the other. Plenty of stories exist about how a movie’s negatives were lost or destroyed in a fire, but the film was rescued for posterity due to a private collector’s personal copy of the film. So the studios occasionally supplement their K-strategy with a little r-strategy themselves. And in fact, they should do more of it – K-strategy is not as resilient to catastrophic events like vault fires (and asteroid strikes, to continue the biological parallel). That’s why disaster recovery leans hard on concepts like off-site backup infrastructure.
Similarly, I think a K-strategy like M-discs, etc, could work to supplement an existing r-strategy. But it’s not our only hope.
All of that’s a very long way of saying that I don’t have much to suggest, other than whatever bulletproof technological solution you come up with, make backups, and store them in multiple geographically diverse locations.