Every school is different.
My school for example, the dux of yr 12 is not the one with the highest UAI, rather it is the person with the highest average HSC mark of their top 10 subjects (this does not need to include english and is moderated not scaled marks)
Techincally we may or may not be allowde to gain total rankings.
However many schools do hand out said ranks.
I do not see the problem in this, and I do not see why you so strongly advocate against these ranks.
Allowing access to these ranks can help assess personal goals, as well as sort out...
The hsc is not some yearly test.
Its a combination of a huge final examination, as well as multiple smaller assessment tasks during the regular school year.
That being said, the HSC is not hard.
Surrounding you with people who study will make you study.
If you're smart and get excellent marks without even trying, then it's not really going to rub off.
I would say on average yes but of course there are many exceptions.
For example someone who does math and sciences to get a uai of 99+ then chooses to do a course such as law which does not relate to these strengths...well yeah you can figure it out.