How about, VCE is a waste of time? I wonder if, when you're a few years into your job/career, you'll think exactly that.
You're assuming that the ATAR is a be-all end-all - as in, you suggest that there's no point to something if it doesn't impact on the final ATAR. But maybe an ATAR is actually no more important than a year 7's mid-year exam result - after all, in year 7, that's really important to a year 7, just like in year 12, your ATAR is really important to you. In fact, isn't life a waste of time? LOL
People will literally forget about their ATAR within the first week of starting a university course (or finishing Year 12).
It's normal for people to always look to the next step in their life/education - but it's important to make the most of the stage you're at. School isn't just about learning things (although that's definitely important,) it's about learning social skills, how to deal with authority, how to communicate with other people. How to become a well-adjusted citizen.
Even if they don't remember it, a lot of the 'foundation' knowledge (both for the rest of your education and like, life) is built in the years immediately prior to year 11/12.
It's just that if you really really know what you want to do, and you know what what you want to do needs you to do (lol), it alls seems so simple and easy. And then you look at a VCE exam and you're like "holy *********************, how do you learn that much in like two more years? why aren't I reparing for this now?".
I don't know.. it all just seems a bit dull.
Related to the above - not everyone knows what they want to do (hell, some people retire without knowing what they want to do,) and people, and their goals, change before they reach/graduate university. Earlier years (prior to VCE) at least allow people to get a taste of everything before they have to specialise (even a little, in VCE).
Also - to put it in perspective, the content of the two year VCE chemistry course is largely covered in one semester at most universities. Some courses are covered in even less time.
All this said, I do agree with this:
Would I agree for tougher academic content (especially for maths and science) for those years? Yes I would, but that's another issue.