Every single thing you cite has been, and will be, copied many times over and preserved that way. e.g. - We don't have the original Bible, we have eleventy-billion copies of it.

I don't disagree that a few things that happen today will be of consequence. I disagree that any single source of that data needs to last for a thousand years in isolation.

There are, I'm sure, one or two examples of thousand+ year old primary sources revealing otherwise lost information that was still relevant in some way. I suspect not many, other than as datum for academics to ponder.

Important information has always survived by copying.