We Are Always Discussing...
...where to keep long/life data. At our house that means photos and video.
Silver images suffer from meltdown when the price of metals gets too high. Ditto rental of Storage either on earth or in a cloud. Urban Legend has it that an NBC exec saved thousands of dollars by throwing out 240 Johnny Carson episodes.
The longivity of writables tends to be related more to the reflective substrate rather than the dies. The use of optical media is about disc size. CD's are a total space waster. DVD's still consume more space than a hard drive. Blue Laser and 12 inch disks sounds very real.
Sony sales people think at least one copy of your TV show should be on ($175 worth of) digital tape. As discussed earlier, a tape dropped out a 6th story window * will probably be more recoverable than a hard drive.
I have not heard much about PROM and ePROM as solid state archival media. If read-while-write, possibly using the image of an electrochemical gap, becomes available, then flash memory would have almost unlimited bit capacity and write cycles per cell, since the gap need only be moved to the next data point, not flushed to one end of the cell and moved back to a data point.
*(no hypothetical pedestrians were harmed in the making of this post)