I think your experience is as good as anything DrageMester as Flash and SD often leaves you without much of a chance recovering data if it 'just' dies and while CD/DVD can be recoverable by using umpteen drives and a managed ISOBuster image, it is in no way a guarantee for a working copy of the document or program.
Enough backups and refreshing backups by making a new after a period of time is the only plausible solution to the problem. I have found forgotten optical backups from around 1997 still working while newer from 2007+ have developed read errors.
Personally, I use hard drives to store backups mostly and never have just one. :flower: