I think I have seen version of this story before but the condensed very was in the NYT yesterday. Its the basic grade inflation story -- from a 2.5 to over and 3.1 -- and as far as I know no one got smarter. The study reported on establishes that the inflation leaders have been private schools. And, it suggests pretty strongly that inflated grades may lead to the disproportionate number of public school graduates in desireable jobs. So, I guess you can, in part, buy your way to a good paying job which then means so will you children. I am not sure the cycle can be broken.
On a related matterm when I heard the story about sophisticated law firms interviewing people on the basis of their GPAs I scoffed. That is about as knuckleheaded as you can get. If a firm refuses to interview someone with a less than, say, a 3.2, do they not allow for the fact that at some some schools a 3.2 may mean average and at others it means spectacular performance. Yet, my big firm colleagues assure me that it is true. GPA trumps class rank and you could be at the top of you class and not get a call because you did not meet the GPA cut off. Seems crazy.