But that is the entire point. It's not about making technically perfect photographs, just for the sake of making technically perfect photographs, it's about developing your technical understanding to a level where you have the skills to achieve your creative/aesthetic choices. I assume when you said perfect, you meant "technically" perfect, rather than how perfectly an image matched the photographer's aesthetic vision.
In the example Steven gave in his paper, it was considered aesthetically desirable to include both shadow and highlight detail (a common issue with bird photography), and by understanding how iso and sensors work, he was able to retain both. But I don't think we should get bogged down with highlights, as the principle is about mastering your craft so you have control over how your photographs look.
As you will probably know, this was what drove Ansel Adams to become such a good technician, because when he started off he was incapable of creating prints that matched how he '"saw" the subject.
But, and it's a big but, "good" photography covers a very wide spectrum of images and how important technical understanding is to achieving your vision will vary. None the less, I think the greater your understanding of technique the greater your freedom to make unconstrained aesthetic choices.
But, its all a matter of degree, and you actually illustrated it in your example. Your technical understanding about blown highlights, allowed you to make an aesthetic decision on how you might want the highlights/shadows to appear in your final image. Steven's paper is just taking you into a more sophisticated understanding of how ISO and sensors work, which gives you a third choice, of sometimes retaining both highlights and shadows in images where you might have previously thought you would have to lose detail in one or the other.
Again, I don't want to get bogged down in the highlight/shadow thing, its just a good example of how technical understanding affects aesthetic decisions.