What has destroyed America was the replacement of the founding Americans with global immigration, all from cultures with big families and zero concern for the country outside of their own family, which is why all of their nations are varying degrees of hell holes, no one thinks of the common future and what is good and decent for their neighbors.
Large families to blame?
What is the family size that you deem acceptable?
Of course, it has nothing to do with family size less than three because they don't have a father present, or a families where the siblings have different, and absent, fathers.