This needs to be solved on the protocol level. Of course, the players who have control over our protocols are exactly the people who don't want this to be solved at all. The next best thing would be to redefine what "bookmarking" is. When I bookmark a page, I want it to be permanently stored on my local machine and full-text indexed. In fact, it's rather ridiculous that after 25 years browsers don't have anything of…
Chromium is almost there.
Chrome had “chrome://flags/#show-saved-copy” which would do you want if you could make Chrome's cache arbitrarily large and persistent, but it appears to be gone now.