I've heard about the rotting, we've got a plan in about a year or two to do a key ceremony to move stuff onto more permanent hardware we can retain for at least 20 years (our roots last 15)
What that hardware will be is still an open question, but probably BD-R HTL.
Also worth noting (I think it's in the script too from memory) we make at least 3 identical copies of each CD in case of CD failure.