The following is what I was told by two experts that I consulted.
Home recorded CD-ROM disks are heat activated dyes in the disk's
layers. They are sensitive to both heat and ultra-violet light (UV).
Dyes can and do fade -- just remember the early Ektachrome film that
faded away after only a few years, and the early Eastman Color movies
that faded in only a year or two.
Commercial CD-ROM's and DVDs are pressed, and have infinitely longer
expected life. Today, the most non-volatile storage medium is the
flash card. Supposedly nothing except a massive EMP will erase them.
Then, just consider that in a few years, MIDI will no doubt be replaced
by a better system.
Re-record every five years and use the latest digital storage programs,
seems to be the accepted archive long term storage concept.
The joys of the digital world... Today I can play a 100-year-old
cylinder record, or run a 1927 nitrate film with an optical sound
track, and get perfect results. Both are _analog_.