This is something that keeps me worried at night. Unlike other historical artefacts like pottery, vellum writing, or stone tablets, information on the Internet can just blink into nonexistence when the server hosting it goes offline. This makes it difficult for future anthropologists who want to study our history and document the different Internet epochs. For my part, I always try to send any news article I see to an archival site (like archive.ph) to help collectively preserve our present so it can still be seen by others in the future.
I don’t think this will ever happen. The web is more than a network of changing documents. It’s a network of portals into systems which change state based on who is looking at them and what they do.
In order for something like this to work, you’d need to determine what the “official” view of any given document is, but the reality is that most documents are generated on the spot from many sources of data. And they aren’t just generated on the spot, they’re Turing complete documents which change themselves over time.
It’s a bit of a quantum problem - you can’t perfectly store a document while also allowing it to change, and the change in many cases is what gives it value.
Snapshots, distributed storage, and change feeds only work for static documents. Archive.org does this, and while you could probably improve the fidelity or efficiency, you won’t be able to change the underlying nature of what it is storing.
If all of reddit were deleted, it would definitely be useful to have a publically archived snapshot of Reddit. Doing so is definitely possible, particularly if they decide to cooperate with archival efforts. On the other hand, you can’t preserve all of the value by simply making a snapshot of the static content available.
All that said, if we limit ourselves to static documents, you still need to convince everyone to take part. That takes time and money away from productive pursuits such as actually creating content, to solve something which honestly doesn’t matter to the creator. It’s a solution to a problem which solely affects people accessing information after those who created it are no longer in a position to care about said information, with deep tradeoffs in efficiency, accessibility, and cost at the time of creation. You’d never get enough people to agree to it that it would make a difference.
Inability to edit or delete anything also fundamentally has a lot of problems on its own. Accidentally post a picture with a piece of mail in the background and catch it a second after sending? Too late, anyone who looks now has your home address. Child shares too much online and parent wants to undo that? No can do, it’s there forever now. Post a link and later learn it was misinformation and want to take it down? Sucks to be you, or anyone else that sees it. Your ex post revenge porn? Just gotta live with it for the rest of time.
There’s always a risk of that when posting anything online, but that doesn’t mean systems should be designed to lean into that by default.