This is what jumped out at me though:
The lack of affordable pre-K means that middle-class children lag behind their more affluent counterparts when they get to kindergarten. More than one quarter of upper-middle-income children entering kindergarten do not know the alphabet, and almost 20 percent of middle-income children do not understand numerical sequence, according to national statistics from the advocacy group Pre-K Now, financed in part by the Pew Charitable Trusts.
Research shows tremendous long-term benefits of schooling before kindergarten. Adults in Michigan who had attended pre-K had a 33 percent higher average income than their peers who had not, according to the 2005 update of a long-term study, The HighScope Perry Preschool Study, often cited by pre-K advocates. Despite these findings, only about 30 percent of 4-year-olds in this country are enrolled in prekindergarten.
I think we’re conflating cause and effect here. The children who get an expensive preschool education are not identical to the children who don’t.
I found the stat that more than one quarter of upper-middle-income children entering kindergarten do not know the alphabet shocking. I would say that in our circle, less than one quarter of children entering preschool at age three don’t know the alphabet. That said, more than one quarter entering kindergarten do not know how to read.