Mike,
While not discounting your theory, having been around "the screen reader game" for well over a decade now I still see more often than not a complete lack of discussing "who controls what" as a standard part of AT education in general, but for screen reader training in particular.
And what's even more peculiar is that when I work with the formerly sighted, most of them know, somehow, who's controlling what when working via point and click.  Even I know/knew that without a lot of formal training, but much of that is because the visuals involved in Windows (or any GUI) are telling you all sorts of things you are not even consciously aware that they are communicating.
When those cues are either taken away, or were never present to begin with, there's a certain added amount of abstraction involved.  But because knowing "who controls what" is so important I find myself on my own little soap box about how sadly lacking formal instruction about this is.  Even just occasionally repeating what I told Mark about how one can really pretty easily reason out "who controls what" absent any deep knowledge at the outset would be immensely helpful.  Not just for screen reader instruction, but in general, we need to be teaching students critical thinking skills, and a basic foundation of those is using logic and reason to clear ambiguity when you have no other easy way of doing it.  The thought exercise, and ability to construct your own, as needed, is just something I could never have lived without.
--
Brian -Windows 10, 64-Bit, Version 21H2, Build 19044
*Here is a test to find out whether your mission in life is complete. If you’re alive, it isn’t.
*     ~ Lauren Bacall