A little bit more about archiving: the unsuitability of flash drives, and one person who uses the M-disc.
The problem never been
just the media, there is also the question of whether or not there will be devices capable of reading the media and software able to decode/play the data format. M-Disk is based on Blu-Ray technology and Apple computers no longer ship with any optical drives, much less Blu-Ray which Apple has never supported.
I came across a stash of magnetic tape cartridges last year months back for a backup magnetic tape drive I used to have on my PC back in the 60s. Out of curiosity I looked to see if I could find a drive for the tape cartridges and they are no longer manufactured and haven't been available on the market for probably 15 or 20 years. (As I recall they were only on the market for maybe 5 or 6 years). There may have been some files there I might like to have but basically they are irrecoverable because there is no player/recorder available. Even if I could find the applicable tape drive, the interface would likely be RS232, Parallel, or possibly SCSI and then there would be the issue of format to read the files. All in all I could spend a fortune trying to recover who knows what data files that may or may not have any relevance today. Even if I could play the tapes the data format has not been supported since probably the mid 1980s and there is nothing available today to convert to a current standard short of hundreds or even thousands of hours of painful manual interpretation and re-entry.
I think Virtual1 has it right. The only reliable archival storage plan is frequent migration from one media to another and in the process reformat the data to a current or, even better, an emerging standard. Given the rapidity of change in the industry the opportunity window for such reformatting and media transfer is becoming narrower every year.
