I think it cliche to believe it's strictly a financial decision. In fact, in the West (afaik) the middle and upper class have a lower birth rates than those below them. Not to get subjective and fuzzy but children are a symbol of hope and promise. Any reasonable adult who is considering children has to ask themselve how to answer when the child asks, "Why? Why did you bring me into *this* world?" Who has a good answe…
Considering that it's the poorer people having more children it seems like the obvious answer is that most children are unplanned or the product of dim people with a figure it out later attitude.
I wonder how many of the "figure it out later" attitude people overlap the "absolute faith in higher power" people? Poorer people possibly have more subscribers to religious faith?
A decline in the religious population, that comforted themselves with wellbeing of their offspring being a matter of prayer and ritual and whatnot, has had some impact on peoples' outlook in this matter?