OT: 1000 year DVD storage

When I was fairly new at the CD-R thing, I began purchasing what was then known as Mitsui Gold media, which claimed a lifetime of 300 years. I can still read what I wrote then just fine--but so can I also read the stuff written on bargain-basement "blue" CD-Rs. I got an 8" floppy in yesterday from a machine shop operation who needed their software rescued. This was Maxell "R-V" floppies; something like "Reliable and Verified". The odd thing is that the data was recoverable just fine (written sometime during the 70s), but the floppy *jacket* was disintegrating--it had developed large cracks and was starting to crumble away. This makes me wonder how many years a "1000 year" CD-R will have on it before the substrate disintegrates, rendering the medium unreadable... --Chuck