You're absolutely right about the books not conveying the point as quickly as they could. @Makerhacks mentioned the same.
I think part of it is that books have traditionally been a certain length because of the economics of books: There's a certain base production cost to creating a book, so they make it longer; also, a book used to need to be a certain width to be seen on a bookstore bookshelf.
Funny, there also used to be a vibrant "pamphlet culture." The English, American, and French Revolutions were powered by these pamphlets. Not only did they help ideas spread, they also made money for those who wrote them.
I'm calling some of these things into question and seeing if I can revive the "pamphlet." I just tried publishing my first shorter "book." We'll see how it goes. It's over here: http://geni.us/4fnQ5
Yes, I like the idea of a pamphlet - or back in the good old days, it was the thing for writers to be serialised in newspapers. Or is this just going back to blogs...?
Will check out your book :)