[rkomorn]

Or maybe we've made life so expensive (in time or money, but "time is money") for people even before having kids that they don't want to or feel they can't take on the extra load of being parents.

Edit: this isn't a very different take from yours, TBH.

[foobarian]

I think that is a significant factor as well - we can debate how related or not it is. I think in this case, there was a gradual ratcheting effect of how much work is extracted from people who would otherwise be contributing to childcare i.e. "the village" of elder people and women. No doubt this has a separate negative impact on the fertility rate. All IMO though, these are speculations without rigorous quantitative backing.