I don’t know exactly when it happened, but nonfiction books have become 80% filler with a few dozen pages of worthwhile ideas. This didn’t use to be the case and if you read a popular book from say, 1910, they are often too information sense.
I have heard non-fiction authors comment on this. It is because there is no market for a pamphlet or novella length work. In science, self help and business people often write influential essays or academic papers. It may make sense to print them because want them as a reference, and the author can expand their ideas. But the problem is that in general they don't need to be ~250 pages.
American non-fiction books seem to have a third dedicated to "the author is awesome and valid in this field, because he or she did this and that talk for this and that person". Very bloaty, indeed.
I agree, but I think some aspect of it is that we are presented the same facts as novel in each genre and if you've read one you've read them all. Whatever the case it's to the point where I quit nonfiction books quickly because I find them boring, where as I used to read them constantly when I was younger.
