Have you been to the presentation? Then you'd know that Sternberg wasn't talking about 'equality' at all. He just said that eg in Kenya, those kids who are good at practical things are considered 'smart'. Hence, actually the smart kids concerned themselves with stuff they needed (practical), and only the dumb kids went to school... funny, isn't it?
But Sternberg admitted, if the 'smart' kid was taken back in time and taken to a school in NY, s/he would end up being 'smart' in an IQ test, too: just bc s/he would adapt to the culture (which means that s/he was intelligent).

The correlation can be explained: you have a high IQ => you're considered good in school => you get good recommendations and education => people will employ you cause they think you're smart...

But SAT scores have no other purpose as to predict _academic success_. That they certainly do, but we must not forget that academic success is not the only measure for intelligence.