tiggy -I guess some would find it odd that you find it odd to hope/aim for a decent uni from whatever age really. Imo, you have to aim for something or you're just going along willy nilly hoping for the best. Of course, one of the beautiful things about life is that it's not a noun, like some of us treat it, it's forever evolving and so too, goals and aims can change. I'm not sure either how knowledge could ever be deemed as invaluable or a waste of time, but then that's just my view.
My ds is also sporty as I mentioned earlier. Ultimately, I'd rather my ds be in a work environment that he loves as opposed to being there just for the money or that being all he was qualified to do. I want him to have as many choices as possible and so imo, the more he can achieve academically and or in sport, the more options career wise he'll have.
Indeed for some children, being in a lower group would motivate them. Like I said for my ds, who is incredibly competitive, he'd hate it and would fight like hell to be moved up. For others too however, it sets up a form of heirchary that crushes the confidence of some of those in the lower groups which they struggle to recover from; the very reason why many people are against them. But you know your ds best, so know which way it would impact him.
You know if we were all the same, it would make for a boring world, so I appreciate too that we all have our own ways of raising our dc and value systems based on our own life experiences.