Interesting. I hadn't heard of M-Disc. Thanks for the link!
The worry of not being able to find a device to read/play back your media is a common one for all storage types, analog and digital. For example, we have hundreds of reels of quarter inch tape from the fifties and sixties down in our library. The tapes themselves are safe (some may need a day in an easy-bake oven), but otherwise they still sound great. We recently had our Studer A-820 refurbished and it's probably in better than new condition, but I worry there won't be any people to do the service, or parts to do the service with if it needs attention in ten years.
The more obscure, the medium, the trickier it gets. We have a bunch of early digital recordings stored on Betamax tapes, that need both a working Betamax deck and a PCM encoder-decoder box in order to be read. Fortunately, those have all been transferred now.
This is why I'm a believer in thinking of maintaining an archive as being an active rather than static process. It's important to be periodically re-evaluating your digital assets to make sure they can be losslessly transferred to current file formats and modern storage media. It was probably never a good idea to simply "put it on a shelf and forget about it", but thankfully with digital assets, these migrations can be lossless, automated, and tested.
Yes, of course. However, backups != preservation. You could have a textbook backup strategy with restore drills and fixity checks making sure that your integrity is 100%. If your audio is stored in Sound Designer II files and your print documents are Word Perfect files, you are probably not being a good steward of your data.
M-Disc BD is doing the right thing by being readable by common consumer drives, though -- I'd be a lot more optimistic about finding or salvaging a BD drive to read some discs in 50-100 years, since even just the PS3 shipped in big enough volume that there will be some forgotten somewhere, than any specialty formats.
The NASA tapes problem (where they couldn't find drives) is definitely a concern on longer time scales. USB seems widespread enough, too.
It would be cute if someone made a self-contained archival device with display, designed for 100+ year lifespan. Solar powered (although generally external power is a simple enough interface that as long as specs are given, it shouldn't be too hard to recreate), multi-language, redundant, etc. Ideally with periodic integrity checks, a duplication function, etc. built in.
Seems kind of like an Internet Archive project, or OLPC or something.
You just described the librarian from the movie Timeline. I think the issue is that we still don't really have a technology or medium that doesn't degrade when unplugged or plugged. Chemical mediums such as most optical media fail, etching is searchable scratchable, etc. Records seem to be the most reliable but are of limited storage ability and require careful storage and switching.
Those kinds of drives are being used by individuals a lot for archiving things like genealogy. I would expect there will continue to be readers (perhaps not <$10) for a very long time.
Etches instead of dye, result is claimed 1000 year lifetime. DOD has evidently certified.
http://www.mdisc.com/what-is-mdisc/
However, I worry about even finding optical readers in 10 years time.