An interesting article (thanks for including the URL) but it (and your comment) suffer from a similar flaw - what makes you think those "interventions" actually had their intended effect?
The school boards may have thought they were ending school segregation by busing white children to the slums, but all they really did was trigger the white flight to the suburbs, and further solidify segregation. "Head Start" was just another government program that essentially tried to help improve the children's mental abilities by replacing [ignorant] parents w/state workers (continuing the destruction of the black family unit), but actually resulted in DECREASING the children's intelligence.
This said, I DO wonder about cultural influences - for example, ethnically, the pre-WW2 Germans were not all that different from other Europeans, but during the war, their military technology (jet aircraft, rockets, atomic weapons) became terrifyingly more advanced than anyone else's. If it weren't for the constant interferences of [the lunatic] Adolph Hitler, the German military would have easily defeated the British and Russians before the US even entered the war.