There is certainly a cost of storing data, and cost should enter the equation. But we're losing a lot of data for reasons other than cost and we don't have a reasonable way of assigning a value to the lost data.
If man was content with the nature of things he would never fly, or go to the moon, or any of the other myriad accomplishments humanity has made. If we can preserve clay tablets from thousands of years ago we can find some way to keep the information we produce today for posterity.
What's the proof for Fermat's Last Theorem again? Doesn't matter, it was just a footnote anyway so let's not bother preserving it. It doesn't matter that it took our smartest minds 358 years of trail and error to rediscover the proof. It can always be discovered again.
Yes, rebuilding civilization from scratch would be a difficult task, taking centuries if not millennia, if no knowledge is preserved. However we do preserve it and do spend considerable effort, what cannot be said about our culture and individual experiences.
Let's keep making preservation easier, and preserving as much as we can. Maybe much of it is worthless, but I guarantee there's at least one document we think is worthless today, that historians 500 years from now will be glad we preserved anyway.
Non-zero doesn’t mean “unaffordable” or “expensive”.
> The hard part is looking into the future…
The hardest part is to understand that the content we want to preserve carries more valuable information about us than about itself.
Scientific knowledge can be discovered again, it’s not something to worry about. The preservation shapes the future views of us, leaving the trace in the history of those who preserve, their life and their experiences. Maybe they just needed to accept their mortality and irreversible flow of time?