Google has this SEO case studies and success stories page since 2019, and they have updated it a few times, I believe. Recently, someone Mariachiara Marsella asked John Mueller if Google could add new case studies.
John Mueller responded on Mastodon, "I find it quite challenging for us to do these since search is so dynamic."
I assume John is saying that since Google Search changes so often, not just the core rankings but also the search features, producing these can often lead the results to be stale - quickly. So even by the time, Google gets proper approval to publish one of these case studies, the study's results may have flipped the other way due to a ranking change or, a feature being demoted, or maybe even sunset.
This then gets me to wonder, will Google drop these SEO case studies all together?
Here is a screenshot of the page as I see it today, just in case (click to enlarge):
Forum discussion at Mastodon.