Yes, you're right, I was simplifying too much (status and brilliance are strongly correlated, so I didn't pay attention to the distinction). However, this doesn't change much - still it's a hypocrisy.
Why do you think that the dishonesty isn't intentional? The journal reviewers demand a specific style and people generally know it. For most papers, the style matters if you want to get it published. If your status is enough high you are more able to choose your style, but a lower-status researcher should first maximise the number of his publications, and the most effective way is to imitate the approved style (which signals brilliance). The authors know it, they are not stupid.
The core of the problem is, in my opinion, that people really buy this signalling. If I don't understand what someone else is saying, I think (more or less automatically) that he's too smart rather that he's a poor teacher. Conversely, if I understand everything, I tend to think that the subject is trivial and the speaker is not much better than me.
No, I don't mean that the news media are biased politically. I mean that authors are biased by the media they use.
I'm learning about support vector machines (SVMs). There are a lot of books and articles written on SVMs. There are also a whole lot of video lectures on SVMs at videolectures.net (see "kernel methods").
People go into much greater detail in lectures than in text. I like to work with text. I'd like to have a text on SVMs that goes into as much detail as videos on SVMs usually do, and works out the ideas behind the concepts as thoroughly, but no such text exists. For some reason, giving a 5-hour lecture series in which you describe the motivations, applications, and work out the mathematical details is acceptable; but writing a text of the same level of detail, which might take only 2 hours to read, is not.
Perhaps this is because writers are motivated to keep pagecounts low. But pagecount no longer matters with electronic articles. Yet writers still don't want to explain things thoroughly. They certainly aren't saving their readers any time by leaving out intermediate steps. A longer article would take less time to read (and possibly less time to write). Another problem with the pagecount theory is that texts routinely include footnotes and appendices, contributing to the pagecount; yet relegate them to the back of the book, as if embarassed of them, despite the fact that this makes them very difficult to use.
It's especially bad in math, in which writers have a long tradition of deliberately concealing difficult steps and leaving them "as an exercise to the reader". For some reason it is considered bad form to write out all of the steps in a proof, even if adding one or two lines could save the reader five minutes of puzzling. I read an electronic article yesterday where the author said, "These two equations are actually equivalent. Do you see why?"
I think people have adopted a set of cultural biases about what is appropriate in lectures vs. in writing by simply counting observations, without thinking about the systematic sample bias. Speakers speak the way they've seen other speakers speak, without recollecting that most of those speakers were instructors. Technical writers, meanwhile, are picking up their cues from authors of textbooks, which are written with the assumption that a person will be on hand to take you through the details; and applying them in situations where no such person will be available.