I've been having this experience recently. I used to be a voracious reader of programming books. But for a long time starting, gosh, maybe over 5 years ago, I just couldn't get excited to read them anymore. Just recently I thoroughly enjoyed reading Designing Data Intensive Applications, and I have just started Streaming Systems, which I'm also enjoying a lot. I think this idea of fluff at different levels of abstraction explains it: I used to enjoy reading books about programming languages and frameworks, but at some point it just felt like fluff and I could no longer get through it. But there are books about techniques for solving particular classes of problem (in the case of my recent reading: data processing) which don't feel like fluff to me. But maybe they will eventually, and maybe you're already further on this continuum and would find these books fluffy as well. I'll definitely be thinking about this fluff at different levels of abstraction model and checking my self-education against it as I go now!