When aging population cannot be supported by enough young hands joining the economy, retirement accounts won't mean much. One can't eat digits, or take them as medicine. Money is as useful as you can exchange them for somebody's work.
If someone is struggling to take care of themselves, why would they have children? Heck, if you have people working 80+ hours a week just to stay housed, when can they find time to have kids?
Cruel societies punish people for having kids. We have a cruel society. The 90s "welfare queen" talk caused the US federal and state governments to gut social programs specifically designed to aid and support people in having families.
For so many people, affording the necessities requires 2 incomes. Childcare either takes out an income or it incurs a huge new necessity.
And then there's always the impact of "what if the child has a disability" in that case most people are really truly screwed in the US if that happens.
I see what you mean, but it's simply doesn't work this way. Raising kids is so life changing that it has no money equivalent, like you can't buy another life. So if that mentioned self-interest is strictly materialist, one won't choose to have kids no matter how generous are welfare programs. We can find moral or practical reasons to support (or tax-relieve) those who does this work for the future of humanity, but it has nothing to do with low birthrate. You can't fix it by throwing money anywhere. It's a problem of ideals.
