Go through 5+ year old bookmarks to find all of them dead, this will show how permanent books seem compared to digital publications. They truly are "time machines" for how temporal information is today.
iCloud is not archival or long term storage, people lose access, or accidentally delete photos or whatever. Meanwhile, all my childhood photos are safely stored as negatives. Of course, my parents' house could burn down and all my childhood photos could be lost, but that's unlikely.
That's one reason that I've been enjoying film photography. I know that my negatives will easily last 50+ years if stored with some care.
We really need a solution for long term file storage for the average person. I plan on putting my digital photos onto archival DVDs at some point and storing them with my negatives. But even archival DVDs have problems, namely that it assumes we'll have DVD readers in 50 years. Meanwhile, we'll still be able to scan photographic negatives in 50 years, and to circle back to books, we'll be able to read books in 50 years.
- "one that benefits everyone": probably wikipedia+scihub, but I think you would have already guessed that. A knowledge database that benefits everyone looks a lot like the internet, minus the serving issues. So probably something closer to ipfs.
Back in the days when the web was just Flash, it wasn't as easy as Ctrl+S to save content you wanted to keep. In a few years, you may need to spin a VM with an older OS to launch a flash-able browser. (https://en.wikipedia.org/wiki/Adobe_Flash#End_of_life)
I wonder if it's easier with java applets.
I had to jump through hoops to get an applet I wrote only 10 years ago running.
I personally prefer mhtml, though with the recent breakage with firefox, I've been doing PDF.
Archiving something interactive.. that's a different story.