The system I propose would be for sure space-consuming. Removing the ads and other unneeded contents would probably help to shrink down the page size though. This is the price to pay to keep the bookmarked content available in the long-term, and I'm ready to pay this "price".

Assuming 1 bookmark per day during 10 years, this will sum up around 8 Go. Storage is cheep enough nowadays so I can support these 8 Go over 10 years. This will probably not be mobile-friendly, but I'm almost never consulting bookmarks from my phone anyway.

Your project seems interesting, thanks for sharing! This may be especially useful to see how you implemented the readability part.