Are nonfiction books too long?
[...]spending a lot of time on the internet, as I have since 2002, has rubbed my nose in something that hadn't really bothered me before then: namely just how overwritten so many books and magazine articles are. Seymour Hersh? He's great. You could also cut every one of his pieces by at least 50% and lose exactly nothing. And I'm not picking on Hersh. At a guess, I'd say that two-thirds of the magazine pieces I read could be sliced by nearly a third or more without losing much. That's true of a lot of books too.The thought I've often had is, "This book has a really good idea in it. But the author really only needed 20 pages to do the idea justice. The rest is just padding because the market for 200 page books is more favorable than the market for 20 page essays."
People have expectations about how long things should be, and people are loathe to violate them. I'd have second thoughts about going to a feature film that was only 58 minutes long, or reading a blog post that was 27 pages.
I think the solution is to find the right medium for what you want to say. Or make any padding so fun to read that people don't mind that you've essentially made your point already.