Oh yeah, taking screenshots would be a nice intermediate decay, instead of the whole video.
You have to think, in general, that we have finite resources, and the alternative is not remember everything in perfect detail, but forgetting things that you do not choose to forget.
After forty-ish years, the limit on personal storage is ever higher. The sum of every filesystem I ever owned will probably fit on two of today's very affordable hard drives. (I should get on that for pre-cloud stuff.)
And decayed versions wouldn't get the author much mercy from bereaved families.
1- moore's law will break eventually. Depending on storage growing is unsustainable. We will need to develop solutions that work when storage growth becomes linear.
2- even if you can save the bits and bytes, there's fidelity loss in soft and hard standards, namely video codecs and connector standards. Not sure how planned decay would fit here, but relevant considering that document from the 90s needs is probably on a weird codec in a pre pata drive. Or even worse an analog medium.
Even if you don't admit that it will happen in this generation, it will happen in the next. We have companies that offer free storage like google, the economics can't sustain that forever, youtube videos are already being purged, google drive limited.
The cost of storing forever is unsustainable over the decades.
You have to think, in general, that we have finite resources, and the alternative is not remember everything in perfect detail, but forgetting things that you do not choose to forget.
Better to choose what we forget.