--- If you accept divorce rate as an indicator for a failed family.
For instance, what if families with two hard-working parents spend less time together but still find a level of contact that's need-filling. They grow neither happy nor unhappy enough to divorce. It's a stable but weak and unnurturing family and perhaps isn't the best place to bring up a young child.
Failure of a family is multifaceted and the op puts forth a theory too strong to be knocked down merely by decreased divorce rates.
(Edited: In light that the statistics the author quoted might be wrong, I'm should disclaim that I don't personally think that the polar-opposites parental style we're talking about here is best. I just want to advocate caution judging family-style health by divorce.)