Google's John Mueller was asked if Google stores a permanent or semi-permanent copy of its own search result pages for future reference. John replied basically saying no, because it is not an efficient use of Google's resources.
The question was asked by Rafal Josko, who asked, "I am seeking clarification on Google's handling of search results. Is it possible that Google caches search result pages, creating permanent or semi-permanent saved copies for future reference? The notion in question suggests that for highly popular queries?"
John Mueller replied, "I don't think that would be useful or efficient. The web is so dynamic, and there are always new queries."
Here are those tweets:
I don't think that would be useful or efficient. The web is so dynamic, and there are always new queries.
— John Mueller (official) · Not #30D (@JohnMu) July 30, 2023
Now, this does not mean Google doesn't have a good memory, it does. Back in 2016, John Mueller said Google's algorithms don't forget, saying its algorithms, at least "some of them, like to take into account more of the history of what has been changing there."
Here is an old tweet referencing that:
They pretty much all do.. Eg, if we find a link to a URL, it's based on the site as it was back then. Some things collect over time
— John Mueller (official) · Not #30D (@JohnMu) October 7, 2016
One such example is 404 pages but there are many many more.
Storing history on signals is a lot more efficient than storing copies of web pages and there is a site that does that already, the Wayback Machine.
Note: This story originally was about archiving webpages, not the search results but John clarified for me in this tweet:
I understood the tweet to be more about the search results pages (our pages), and not the web pages in the search results (site-owner's pages).
— John Mueller (official) · Not #30D (@JohnMu) August 1, 2023
Forum discussion at Twitter.