Chicago CEOs might live in Lake County, but not everyone in Lake County is a CEO. When your elderly financiers bought or inherited their house in Kenilworth or Winnetka, their town was still closed to ethnic minorities. (A girlfriend’s father, who was a professor at Northwestern in the 60s, was once picked up by the Kenilworth police and escorted out of town because he was house hunting while Jewish.) Kenilworth isn’t a whole lot better today, but places like Deerfield have really changed.
ETA: They’re still absurdly affluent, of course.