How is it that people keep getting away with dragging a blog post out into an entire book?

I like blog posts. I read a lot of blog posts, and when I really like a blog post I may binge its author's blog until I physically can't continue reading them. (I've been reading Cory Doctorow's blog all day.) But I can fucking tell when something is being dragged out, when an idea could've been conveyed in far fewer pages. Why do nonfiction airport books keep getting away with this?

Is it just a prestige thing? Serious Idea People are above mere blog posts, so an idea that takes ten minutes or less to convey is not officially recognized until it's attached to a shiny paperback? At which point Serious Idea People will all finally recognize the blog post and treat it as isomorphic to the book but less annoying to read, like a broke engineering major using cliffsnotes to avoid reading 19th century literature.

There are books that are at least made from collections of blog posts that add up to a similar length. They can still suffer from poor quality due to some of the blog posts being superfluous reiteration of the thesis, and there's always the cases of shit bloggers compiling their shit blog posts into a paperback for a veneer of respectability. But at least it's not a complete waste of time to read them if the series of shit blog posts actually add anything new after the first one: I might laugh at them rather than be bored to tears.

Anyway. Thanks to the podcast guys for suffering through so many terrible books that suck ass to read. I know I'd drop them the instant I felt like I already knew what the rest of the book contained, and with One Book Theory constantly being reaffirmed this podcast wouldn't even function if it followed the same standard I do. Imagine an episode on The Coddling of the American Mind stripped of everything you expected out of that book via OBT, it would be like five minutes long! I'm a slop enjoyer who likes listening to things that conform to my expectations, so a full hour on a book like this isn't a waste of my time, but I'd be pretty hard pressed to read the actual book the episode mocks. The paperbacks on my shelves are 90% trashy fantasy novels and it's going to stay that way.