Thanks for calling me sad, that clearly shows that you don't know me.
The fact that your MIL loves to spend time with their grandkids doesn't invalidate that if she is sick, she might still feel responsible and push herself if there is no one else to take care of the children. Not the fact that many people don't have the luxury to have the grandparents close. Some live in different cities, other have lost their parents and there are even orphans that have children. Or people with old/sick parents that need to be taken care of too.
You want to pretend that your situation is valid for everyone and that "of course there is help" when in fact, people having help or not depends on luck and how much money they have.
If I were to use my family as an example, Not only my mother and MIL are alive, but both my grandmas and my aunts are around. Plus I have money to pay for childcare. But my situation is not everyone's situation. I'm lucky, but I won't force people who is not so lucky to go through a pregnancy and giving birth for an unwanted children precisely because I'm aware of how much sacrifices are needed and how difficult it is if you aren't as lucky as me. Hell, it is difficult even when you are lucky.
Again: 17 million hungry children at USA. Acording your model, either those children doesn't have grandmas or their grandmas can't feed them either. No, there is not enough help for women who want to be mothers, much less if we add to that the unwanted children. Otherwise, you won't have 17 million hungry children. And the more I think about it, the more true it becomes the part about me being a "sad, sad woman", since 17 million hungry children is a very good reason to be sad. Sure, the children in my family are healthy and happy, but I can still feel sad for those other children.
You might want to consider the children that have already born before you force people to bring more children.