alt Hacker Newseven before LLMs you could/can get a lot of info on the web. Most ideas presented in books exist on the internet somewhere, quite a few pass through HN. In the 90s and early 2ks I used to hoard books, but now, not so much, I get a few through my library these days but a lot of times I just find the book is padded out to be a book and the meaty bit of the book is usually tiny.
I also find that docs have gotten a lot better over time as well. I feel that Y2K era of numerous large tomes was largely to fill in the gap left after software publishers stopped shipping even their full price boxed software with meaty manuals, assuming I guess that help menus and GUI context (or maybe even Clippy) would get you there. Even some of the enterprisey software- Oracle comes to mind- would ship with like 6-10 volumes of reference information but very little in the way of a getting started guide that showed you how to get basic stuff up and running or what best practices were.
The web got a little better, and what drove brainshare and usage was a good experience getting started with reasonable defaults and good docs to get you started. API design is also much better these days- I was trying to find some examples of how unintuitive say MFC (Microsoft Foundation Classes- big in the win9x days) apis were, but a lot of those docs seem to have disappeared- here is a stackoverflow/experts-exchange links that show how non-intuitive it was: https://stackoverflow.com/questions/3255207/window-handle-in... https://www.experts-exchange.com/questions/10018203/How-to-g...
Motif on the Unix side of things was a bit better, but not much. You really needed a good book to walk you through things in a more understandable way.