Honestly paper, parchment and stone have a pretty bad record as a format. They either degrade or even if preserved can become unreadable (e.g. Linear B) without a surviving linguistic community. Even when the text survives and is rediscovered, translations produced with century-scale gaps often lose subtext or connotation that would still have registered across a narrower gap.
I'd suggest an unbroken chain of oral transmission...
Much more slowly and gracefully than any digital medium we have concocted so far (save for core rope memory, maybe).
> even if preserved can become unreadable (e.g. Linear B) without a surviving linguistic community [...] translations produced with century-scale gaps often lose subtext
This pertains to the message and not the support; also, I'll take missing subtext over missing text any day of the week, thank you very much.
This is a high-tech vault located in the Arctic. Compare this with manuscripts that survived centuries by virtue of simply being on a library shelf in some random monastery.
Furthermore, the vault contents are stored on piqlFilm, which in turn uses Boxing barcodes [1]. So, they literally rely on an analog support.
I'd suggest an unbroken chain of oral transmission...