A bit of a tangent here, but something I have always wondered is just how MUCH information was lost in the as-of-yet never satisfactorally explained burning and subsequent loss of numerous books in the library of Alexandria. Then you have whole other compiled sources of information like the tens of thousands of clay tablets amassed by Ashurbanipal of Assyria in his time. And this is just written down knowledge, no other medium included.
I have absolutely no idea what percentage of all the world's knowledge is actually available on the internet, much less readily available. To tell you the truth I struggle to ever stumble back upon some of the articles, tutorials, how-to sequences, etc that I once worked through just a decade or decade and a half ago. It just seemingly isn't there anymore (and some of it may literally not be on the regular internet any longer, if a server went down or websites expired, etc).
Interesting topic. Huge topic really, haha. And how much is lost over and over and over again each time whole chunks of the world put themselves through yet another onslaught of war, only to lose whole waves of people spanning multiple generations, and if enough of the "right" people are lost each time, people possessing especially more keen or observant minds, or just possessing certain skillsets deemed more "desirable" for their particular time, only to never be rediscovered or happened back onto in one or even a few lifetimes?