Ludicrous suggestion time!
Since CDs / DVDs are not permanent. (Some of mine have self corrupted after only a few years ) how about this?
Transfer onto VHS magnetic tape? Longer lived than discs.
The problem with almost everything archived is going to be reading it several years down the line.
What was "state of the art" a few years ago is now obsolete.
Even with pen and ink , the ink fades and the paper rots. (Not many 1940s era newspapers still around )
Maybe quill pen on vellum IS the way, before writing becomes a lost art.
Howard.