Digital data is arguably more fragile than analogue, offline, paper (or papyrus, or clay tablet) media. We have documents over 3000 years old that can still be read. Meanwhile, the proprietary software necessary to access many existing digital data formats is tied to obsolete hardware, working examples of which may no longer exist, emulators for which may not exist, and insufficient documentation may exist to even enable their creation. Just as one example, see the difficulty in enabling modern access to the BBC's 1986 Domesday Project.