Society pays a lot for children as well. Including members without children.
A child might cost its parents somewhere beyond $200k, the parents only get a tiny fraction of this from the state.
And the public paying for education is not a subsidy for parents in my view, but an investment into the children, i.e. future taxpayers (=> the parents don't really gain from that).
All the benefits that used to be there (adolescents helping with farm/work, children taking care of aging parents) became more and more irrelevant, but general costs of raising children (to parents) have not decreased at all (and "reputational" cost of just skipping parenthood is at rock bottom, too, so that is no longer pushing prospective parents towards economically irrational decisions, either).
Yet another reason for others not to chip in your bad ROI decisions then
As you point out, Finland famously has incredible family support, and also a birth rate under 1.3.
1. Lump sum, pretty big (like year worth of salary or close) payment on birth
2. Works for first child only.
That's it. So, it kinda works, but very limited. Increasing sum did not increase birthrates, if I remember correctly.
Anecdotally, when my grandmother did not birth a child for two consecutive years in her thirties the village priest came to investigate (!!). Expectations have shifted massively since, and the single/dink lifestyle is way more "acceptable" now.
How is it in Germany? I would guess better
also on the attractiveness for women, germany being less traditional means that more women are willing to break traditions, so even if the situation there is better for them, women are still less interested, which means the effect in the end is the same.
People who are not flying are also financing airports from taxes.
This is why butthurt "childless pay taxes for schools but not using them" is super stupid