That's right, but regardless of how "extreme" testing is, archival grade DVDs have performed as good as M-DISC, and Syylex has surpassed the rest by a huge margin. Syylex promised the same lifetime as M-DISC (unlike archival grade DVDs). I think the results are good enough to see M-DISC either doesn't live up to the expectations or archival grade DVDs exceed the expectations. Either way, bad news for M-DISC. If Syylex hadn't bankrupted, it would have been the best option of course.
Yes, what I mean is that - set aside the "glass" disc from Syylex - we don't know if both M-DISKs and archival grade DVDs suck or excel, let alone how long they actually last (readable) in the real world.
IF my last guess in comparison is correct, 100,000 hours at "normal" temperature/humidity is roughly 11 years, but it may well be that without "cooking" them at 90 C°, the duration is for both 200,000 hours (or whatever) ...
250 hours @ 90 C°/85% humidity, how does that compare to - say - 100,000 hours at a "normal" 10-40 C°/30-50% humidity?