> I don't have an application that requires ten thousand years of storage but I'm sure someone out there does!

A) record (a representative cross-section of) "everything" and leave multiple copies where future archeologists might find it. To avoid things like how present-day archaeologists apparently have holes in the kinds of things they can find, due to different social classes not leaving equally-robust trails.

B) this is "at least as long as I could possibly care about" storage. If I need to retain say financial records for seven years, and then later the government retroactively increases that to 20 years, there's no need to re-archive it all onto new media.