I like the coinage "trendism"! I too wrote a piece a few years ago about the problem of reverse-chron in the design of too many tools: https://this.org/2017/11/15/social-media-is-keeping-us-stuck-in-the-moment/

That advice about library sales is great -- I'm totally going to try that!

Randomness is indeed a great way to inject serendipity into one's reading and contact with culture. That point about re-encounting one's older reading and/or notes is spot-on -- a while ago I started working on an app that would randomly serve up clippings from my note-taking for all my journalism of the last ten years. The actual functions for randomly-sampling and displaying stuff was easy to write; where I foundered was on the project of crawling my notes and formatting them in quanta useful for the random-serving-up-of ... I couldn't quite settle on the right way to chunk things: Paragraph? Sentence? Etc? Entire document? I need to return to that ...