From the inability of NASA and the DOD to reverse engineer their own tech from the 60s/70s, to the alleged humor that Blizzard has a bounty for anyone who can provide them with the original WoW code
Media storage is only as good as the hardware and the networks they support, time, corruption, and meat-space disruption will make it inevitable that vast amounts of data will be lost
'Internet never forgets' my ass
The knowledge on how to decode a medium encoded within that medium itself. A system that only exists because it exists and can only continue to exist with it's continued existence.