It may not be true for the elite schools, but getting into those schools is winning a lottery, even for kids from rich families. Consider that in 2011, 6.2% of the applicants were admitted into Harvard (http://www.thecrimson.com/article/2011/3/31/percent-class-st...). There were certainly lots of extremely bright, hard working, likely-to-be-successful kids in the 93.8% who were rejected.
The article's point is interesting, but looked at through this light, it's basically saying "I did not realize I could enter this lottery."
The parent commenter is pointing out that most kids from rural areas will end up at public state schools which do not have the resources of these elite private schools.