...as for my 20 year time frame, I offer up the examples of SyQuest & Zip. They were never meant to be archival, but the danger remains that when you have magnetic or optical media, you risk the reader/player not surviving the required storage time frame or being able to interface with contemporary technology even if it does.
Neither Syquest nor Zip ever achieved the kind of market penetration necessary to define a format that can withstand the test of time. I think anyone who committed to either of those formats for archival purposes was just not thinking particularly long term.
I know that the best archiving scheme must face market forces, but the right system will have no problem gaining market share if it fulfills the requirements I have proposed earlier. I don't care what form it takes, as long as it solves the problem. I can see a very simple / low cost authoring system that can be had for around $5K in quantity and that has media costs of pennies per linear foot. Its a ripe market opportunity but it needs to be aggressively priced for rapid market saturation and capitalized by someone with a long term view. Someone like Kodak could make it happen. But it must take the form of an appliance that can be acquired by a post house or service bureau and the company should count on the bulk of their margins coming from the media and a one-time storage fee. If a low margin, high volume model could be developed, its feasable that such a system could be cost-effective enough to archive all the production assets, not just the finished version.
Uhhhhhh.....
Didn't you just describe LTO? (I would say LTO5, but the LTO system is designed to be backwards compatible for at least 2 versions, so it's something of a moot point...)