I'll argue reading non-fiction books is not solely about information. It's more about insights and actions, actually. You might have a lot of information, but if you can not use them, then they are as good as useless. The hardest part is not acquiring information but gain a personal insight from what the author presented. And to do that, you have to convinced yourself; set yourself in the mind frame and the experience of the author to gain the (same or different) insight. And that takes more than a bit of time to read and to digest. If you really want to understand deeply, you have to answer the question of how did the author come to these conclusions. That takes even more time than just reading. That is also the reason why distilled summaries (like these on Blinkist or 12 Minutes) read almost all the same and feel outright trivial. The key ideas are often simple enough. But how to get there is in reality the big question.