good questions. The truth is that nobody knows for sure.
CISD/NIST have performed some initial accelerated aging studies with dvd-r media.
They concluded that PIE of 280/8ECC floating window in reading a disc was a relatively good max level under which media tended to have safe margin for longer storage.
However, it is possible to lose even ‘good burns’ that are just made onto really poorly bonded media or otherwise unstable media. The chemical stability of the disc is what really matters in long term storage. That stability is determined by chemical / disc quality and storage conditions (radiation, gases, acidity, solvents, humidity, temp).
So, your best bet is to use high quality media (say metal azo, which MCC claims over 100 years of storage in stable archival conditions) AND make sure the burns read ok.
PS Let us not foget, that the errors are in the reading, not on the disc. Discs don’t have 100-280 PI errors, it’s the drive that reads the disc that sees those errors (due to lower level errors on the disc).