Hell, pulp paperbacks, probably the worst books for longevity, from 70 years ago are usually fine as long as they've only been gently read a low-single-digits n

Hell, pulp paperbacks, probably the worst books for longevity, from 70 years ago are usually fine as long as they've only been gently read a low-single-digits number of times and haven't gotten wet/mildewy. They're often past yellowing and into browning at the edges, but they're fine for reading. Hardcovers from the 19th century are pretty common. Tons of low-value ones (textbooks, fiction by at-the-time very popular authors who've been forgotten) floating around at a couple dollars a piece in flea markets here in the US, and I bet even older books are somewhat common in Europe. Lots by famous authors but of course those are usually more expensive. Most of those weren't finely-printed on modern archival paper or anything like that, and haven't been kept in archival conditions, but often have a few years of hard-reading life left in them (and much more well-shelved), so 150-200 years is a fairly easy age to achieve for gently-read hardbacks using cheap (but not the very cheapest) materials. Maybe more if you re-bind them once or twice, or they're very rarely read. That's without even getting into really nice material and binding, or very expensive non-paper for the pages if you're very serious about keeping a book in good shape for centuries. Not even tape comes close—we don't have a really good archival format for digital stuff yet, let alone one that normal people may have a bunch of in their houses (like books). Maybe one of the several long-lived storage formats under development will take off one of these days and our digital storage will get a bit less risky. Right now it's pretty bad, only saved by being extremely cheap compared to other options.