I think in many instances larger families are inclined to have problems. Once you get beyond a few children, the one on one parental attention wanes, older children have to start caring for the younger ones etc. There's also the need to be able to provide for all of them, and in modern times, college degrees are expensive and don't go as far as they used to. There are so many things to consider and there is no "blanket answer".
Some families are better able to manage large numbers, but I have a family member who has 9 and refuses to stop. She cannot care for all of them properly and burdens the grandparents with helping to raise them all. The father won't keep a job and she has to work and they are in poverty. Their grades are awful, one of the oldest ones is just this side of functionally illiterate and is still about to graduate high school (that's a whole other subject) and it's all because she is ill equipped to raise a huge family and meet all of their needs. She loves the attention she gets from having such a large brood though.
I get upset with her because she doesn't seem to mind burdening others due to her belief that God is blessing her with them, when it's actually a biological function she could control if she chose to. She is being irresponsible bringing more children into the world that she cannot afford or attend to all of their basic needs.
Are all large families like this? No, but it sure makes it hard for each child to get the solid start they need in life, the education, the parental involvement etc. I am thankful I came from a small family every time I look at hers.