I wonder about those things too. My mom was proud that she not only went to college, but graduated - her friends were their for their 'M.R.S'
But I don't think arranged marriages are necessarily going to be better or worse than love matches for sorting folks along the dimension of IQ. In a way, a good matchmaker has lived in a community for a long time and 'knows her business' - why not leave such an important decision to a professional?
But our pool of possibilities with travel, college, and workplace is so much larger than when we lived in small villages. That seems like it would make some difference. On the other hand, if you live in the right small village, well there is more of a chance of genetic drift, so perhaps one would be better matched. In my grandparent's generation, lots of cousins married cousins (not first cousins) and lots of siblings married pairs of siblings from other families. When one of your siblings gets married, aren't you checking out the unattached family members on their side and mentally reviewing who is unattached on your side? I know I am.
Another possible big change in our lives that I would guess I'm seeing is that as women have more choices, fewer really bright ones become teachers. What a change I've seen in my life time! I think most of my elementary school teachers were MG, and I don't come from a fancy town.
Well, Mum - no answers, but you are certainly not alone in speculation. Sometimes when someone asks 'why' I spend so much time here, I think 'hey - any of your kids could be my child's future spouse/boss/best friend so if I help you figure out how to keep them happy and hardworking, then it comes right back to me!
Grinity
