It's not all in the genes.
This is a very intriguing post by Half Sigma, on memory versus active intelligence. There's a rich field to be explore here, about getting and maintaining advantage.
It's also about starting early - as early as pre-pregnancy, according to a doctor friend (and Phil Hammond). For example, the womb needs to be in good condition, not shrivelled by a smoking habit. It''s said that the foetus will steal whatever it needs, so surely there needs to be plenty of the right vitamins and minerals in the mother's body. And after birth, early, plentiful and positive emotional and intellectual stimulation.
Then there's education - being taught principles and strategies. I read somewhere that in Japan, trainee professional Go players aren't allowed to learn through play until their reading has brought them up to 1-Dan level (sort of like Black Belt). That's instead of learning the hard way. In any case, does the hard way actually teach you? Or do you decide to try harder next time? Or tell yourself the other guy was lucky? Or maybe just give up?
And the right social and professional connections. And choosing the right career, and the right place for it to flourish.
Some years ago, I watched a programme about a very senior British civil servant/politician in Hong Kong at the time of the handover to China. He quoted what appears to be an old saw, though I hadn't heard it before: "Eat right, work right, marry right."