Might be a strange question to ask, but do you "get" anything out of reading non-fiction? Like, is there a substantive benefit you gained from reading these books?
As an adult human, my life experience contains too many variables to reach scientific certainty about the entire causal chain.
However, my early 30s were still marked with a heavy insecurity, ennui, lack of direction, failure to focus and achieve in the workplace, and failed romantic endeavors.
I began with work on boundaries and understanding self by Henry Cloud, ways to achieve like Find Your Strengths, and even business related work like Good to Great.
Flow was an excellent part of this collection, as it helped me turn work into something more enjoyable and progressive. Drive was very neat, and I really enjoyed Your Brain at Work.
I also have a personal interest in education, so I read a lot on that, including by Sir Ken Robinson. And I read Power of Habit.
Overall I think the things I learned improved my habits at home and at work, grounded me, improved my confidence, and made me a better resource for others. (Of course I must not assume I always have the answer or am absolutely right just because I read things in a book.) In general when I have deep conversations, I seem to be able to follow along and better understand how people work and how relationships work.
I'm very happy with my job, feeling very productive, significant and learning new skills (in my 40s). I've been married 6 years and have a very high satisfaction with our marriage. There's still a struggle with getting everything done I want, like gathering firewood for the winter, but largely I feel that I rise to meet my responsibilities.
Now I can't say how much came from dedicating time and effort into learning, and how much comes naturally from experience and age. But I certainly don't regret any of that self-education today.
Simply: reading is communication over time. It enables earlier others to share their thoughts and insights. Often, as suggested in this thread, ideas arising in one domain have relevance in others --- they provide insights, clarity, metaphors, understanding, mechanisms, skills, ...
It is an interesting question, and one I think about once in a while. My recall of specific facts from books I've read is pretty terrible (not sure if this true for others, or if it is related to my aphantasia in any way). That's true both for fiction and non-fiction I read. That said, I do feel that a certain amount of knowledge does remain, somewhere below the surface. I can carry on a conversation on a variety of topics, concepts that I have encountered before are processed faster, my worldview shifts and expands. I have general awareness of Mihaly Csikszentmihalyi and his work :) Is the benefit substantive? Hard to say. But I enjoy the process and get to be a slightly more well-rounded person, so why not.
It's a perfectly fine question. A lot of nonfiction books contain their authors' pet theories, along with a bunch of anecdotes and handwaving to make them seem justifiable or even scientific. Some of them quote "scientific" research from fields like psychology - but that research itself is hardly scientific (hence recent replication crisis) and is also used out of context in the book.
As for the question if these books add value - they certainly provide entertainment for the reader, but they may also warp his view of the world (if the reader is not careful, they may become convinced that the book's thesis is true even if the evidence/ancedotes laid out are hardly conclusive).
This seems like a very bizarre characterization. Technically On the Origin of Species by Charles Darwin and Relativity by Einstein are non-fiction. I'm very happy to say I've had my mind warped by their pet theories.
They both present compelling evidence and can be thus classified as science. Darwin spent a couple decades accumulating evidence before he wrote the book.
Also, majority of non-fiction textbook are about psychology, economy, sociology, history etc. which are vastly more intractable than biology and physics.
