I don't read the Daily Mail. I don't believe the crap they put in there. Do you have a scientific source like the one I linked you? One with studies?
I was also given some good advice a few years ago by a businessman. He told me ... you will likely be the average of your friends. If all your friends are drop outs and junkies, you'll be one too. If your friends are all top bankers and business leaders, guess what you will be doing for a living.
So it is of no surprise to me that an average IQ rich kid does better than a brilliant poor kid ... they will network better. But also they are much more likely to be smarter on average. The brilliant poor child is as rare as hen's teeth.