FWIW does any of it remain on archive.org? They have some really great collections on there, and writing on digital archiving, like how to preserve CDs as best as possible (spoiler: the brand of CD is a large factor).
From: https://archive.org/about
> A single copy of the Internet Archive library collection occupies 145+ Petabytes of server space -- and we store at least 2 copies of everything).
Thankfully they have a few backups around the world, but there are still plenty of plausible events which could render the data useless. In contrast, physical mediums like books, vinyl records or microfilm/microfiche can last for hundreds of years.