Here are some books I've read from semi-recently which felt like they had "about a blog post's worth of useful information" (probably an exaggeration, but still):
Oftentimes such books will repeat their core points over and over, or include a lot of detail which feels irrelevant/overly technical and I will soon forget. In my experience, it's surprisingly common for books written for a general audience to include technical details and descriptions which are only meaningful for a specialist. Even though the book is hundreds of pages long, and there's plenty of room, the author still doesn't provide the necessary background knowledge to interpret the technical details they're including.
>Most books I read have a lot of information, if they didn't I would stop reading.
If you go to a bookstore and flip through a lot of the recently released stuff, especially the celebrity books, a lot of them are really thin on content. Especially if you grew up reading dense novels and textbooks, it can be surprising to see what the mass market for books is like.
That's a tiny slice of the books on the market though and these are books that weren't already proven to be good by the test of time. I don't think most books sold are recently released by a huge margin. The only publication where recently released matters are specifications, papers, documentation and news, but these tend to be mostly online or digital these days.
What books are you reading? And why are you reading them, after having read the cover and being able to read the summary?
Most books I read have a lot of information, if they didn't I would stop reading.