I think you are looking in the wrong direction.

• Matrilineal vs patrilineal societies are not a product of the locally available resources. In the ancient Mediterranean region the old matrilineal societies were overtaken by patrilineal invaders, without any change in the available resource.
• concentrating resources and effort on fewer children can make sense if you have quite some developed means. If you rely on your arms for farm a field, you better have as many arms as possible. It's only when you have a tractor that you can go easy on the arm count. Same for health care: if you have the means to take care of sick/wounded people, then it make sense to invest in few of them, but if all you have is murmuring some hulla hulla and spreading mud mixed with saliva, you better have faith in the big numbers and make as many kids as possible, since by chance some of the will survive.

I heard stories from my grandmother that in her times, just 100 years ago, for a pregnant woman it was common to go work in the fields until the very last moments before delivery and then get back there as soon as possible, the concept of maternity leave being not even an abstract idea.

This is maybe the only difference you can play on: with more men at disposal, a pregnant woman can be relieved from heavy duties and be better taken care of during her pregnancy, delivery and after delivery, increasing the chances that she can survive and proceed further in the baby making job.

I think you are looking in the wrong direction.

• Matrilineal vs patrilineal societies are not a product of the locally available resources. In the ancient Mediterranean region the old matrilineal societies were overtaken by patrilineal invaders (source), without any change in the available resource.
• concentrating resources and effort on fewer children can make sense if you have quite some developed means. If you rely on your arms for farm a field, you better have as many arms as possible. It's only when you have a tractor that you can go easy on the arm count. Same for health care: if you have the means to take care of sick/wounded people, then it make sense to invest in few of them, but if all you have is murmuring some hulla hulla and spreading mud mixed with saliva, you better have faith in the big numbers and make as many kids as possible, since by chance some of the will survive.

I heard stories from my grandmother that in her times, just 100 years ago, for a pregnant woman it was common to go work in the fields until the very last moments before delivery and then get back there as soon as possible, the concept of maternity leave being not even an abstract idea.

This is maybe the only difference you can play on: with more men at disposal, a pregnant woman can be relieved from heavy duties and be better taken care of during her pregnancy, delivery and after delivery, increasing the chances that she can survive and proceed further in the baby making job.