If you can see the bits, you can figure out raw PCM. It's super trivial.
If we're worried about being unable to access the bits at all, we should consider etching them into metal or printing them on archival paper. Tape won't reliably last hundreds of years. But for now we can keep bits alive pretty easily, with low but nonzero sustained effort.
If you have a lot of tapes, a dozen digital copies will survive a lot more incidents than the originals, and be a lot cheaper than analog backups along with no generation loss.
If we're worried about being unable to access the bits at all, we should consider etching them into metal or printing them on archival paper. Tape won't reliably last hundreds of years. But for now we can keep bits alive pretty easily, with low but nonzero sustained effort.
If you have a lot of tapes, a dozen digital copies will survive a lot more incidents than the originals, and be a lot cheaper than analog backups along with no generation loss.