Humans are quite bad at estimating the results of different interventions, if the feedback only comes years later. One needs only to see the plethora of different parenting guides and opposed schools of upbringing thought. Such variety couldn’t maintain itself if it were easy for parents to see which methods worked and which didn’t. Thus parents are poor at knowing what they need, and hence make ineffective consumers from the economic perspective.
Also, “a lot of parenting techniques are procedural, rather than declarative.”