Penelope Trunk says this (I recommend reading the whole thing to get her full argument with links):
Kids with educated parents do not need to go to preschool. So preschool primarily benefits kids with uneducated parents. Preschool can help those kids start out on equal footing with kids of educated parents.
Children who have educated parents should be playing when they are preschool age. They learn through play. They do not need to learn to sit still and stand in line and play only when the teacher says play.
The idea that kids should learn to read, write, and add when they are very young has been thoroughly disproven, and in fact, this sort of structured environment is so bad for boys that it puts them on an early path to being labeled low performers. This is why the rich don’t even bother with preschool—they know their kids will be fine without it. ...
Here is my proposed solution. First, promote marriage. Yes, it’s judgmental and pushing cultural values onto individual citizens. But so is universal pre-K. Marriage, however, is much more successful at giving kids a good chance in life: keeping a marriage together decreases the chance of a child living in poverty by 80%.
And let’s go after deadbeat dads. The majority of low-income kids are not living with their dad. I do not believe that low-income moms are different than high-income moms; I think l0w-income moms also would choose to be home with their kids over working full-time.
New York City increased the amount of child-support collected by 50% in the last ten years. We can use the same tactics across the country.