Fertility Incentives Debate

You have it backwards. Most industrialized countries are below the replacement rate even with current monetary incentives (e.g. tax breaks) to have children. Kids are an enormous financial burden to parents, and financially they benefit the wider society, not the parents. Assuming you don't want social security (or its equivalents) collapsing, you want to incentivize having children at least to the replacement rate.

If people having children is a public good, maybe it shouldn't be disincentivized?

Without a welfare state, sounds like good incentive to have lots of kids!

Why incentivize people to have children when there is no shortage of them?

It would be better if they gave incentives to their own for having children.

I guess one option is to reward everyone for having children. Although this only makes sense if you want more children in your country. Some countries do. Singapore apparently has a giant "baby bonus" of incentives worth $121,400 USD to have 2 children.https://en.wikipedia.org/wiki/Baby_bonus

To be blunt, this is a tragedy of the commons scenario. The costs are primarily on the parents, and then society gets the benefits (in the short term, of the spending by the parents, in the long term by the productivity and spending of the grown child). This is why smart policy makes it easier to have children--because overall some level of population growth causes economic growth which makes everyone's lives better.However, I don't know of any country in the world that has cracked

I don’t have kids. It’s valuable for the greater good of society not just a child. You have to live with the eventual adults that develop under a system that supports caregivers or one that does not. If we don’t look beyond the first effect we can miss that.To further the point, the decision whether to have a kid can be influenced by how that affects someone’s own finances. These programs put a finger on the scale to encourage having children, something that financially to the individual does

May be that is why they are starting to incentivize families to have more than one child.

This will just lead to more people having kids for the paycheck they provide. Parents who view their kids as a source of income, instead of as a life they are responsible for nurturing, are generally not great parents. A bunch of bad parents with bad motivations leads to a generation of dysfunctional people.