The problem with most texts is that they're linear and structure-less, which means it is hard to efficiently extract information from. I should be able to decid

The problem with most texts is that they're linear and structure-less, which means it is hard to efficiently extract information from. I should be able to decide exactly how much of a text I want to read, depending on how interested I am. If text would be hierarchical, with top level items being summaries, and each successive (indented) level going into more detail, I could tailor the reading of the text to my needs, interest level, and prior knowledge of the subject. Why do we not write like this?