Cmon what you are saying is 100% false. Men are 100% capable of caring for infants and toddlers. Formula exists and there has been no large scale study that has shown a significant long term impact for formula usage. All benefits of breastfeeding are minor or unable to be separated from characteristics of the mother.
Women entering the workforce is not the death of child achievement. It is not even parents having time since there was only an extremely narrow window where the one parent household was a thing and it wasn't even the majority of the population. Income has always correlated with achievement and wealthy parents pay money for their child's enrichment not particularly engage with the children themselves. There are kindergarteners at my kid's school in tutoring to get them ahead. These kids are not even behind. That's not the mother spending time on their kid that's boosting the test scores in my district. It's wealth.