Why does our book publication culture consistently produce books around 200 pages long? I love reading long books that truly have something to say, where a high signal-to-noise ratio justifies a soul-crushing page count.
The problem to me is when an author has an idea that can be clearly, effectively communicated in 50 pages, but then expands the manuscript by 4x so it can be a real book. There are multitudes of books like this that would have made a great essay. You have to mine the value from such books by wading through section after section of anecdotes.
This is one reason I really hope short(er)-form publishing (ala Kindle singles) takes off.