I thought all libraries using optical discs technology migrated to M-DISCs already.
Do we actually know that M-DISCs are much better than ordinary discs regarding longevity? I wasn't really convinced by the wikipedia page
The accelerated tests actually performed on them may (or may not) be reflective of longevity in the long time.
Are they "tougher" than other disks? Yes.
Will they last 1000 (or only 100) years? We will see.