'Polgar and her two younger sisters, Grandmaster Judit and International Master Sofia, were part of an educational experiment carried out by their father László Polgár, who sought to prove that children could make exceptional achievements if trained in a specialist subject from a very early age. "Geniuses are made, not born," was László's thesis. He and his wife Klara educated their three daughters at home, with chess as the specialist subject.' Source: wikipedia
The difference in their story from that of Chua is that the experiment involved creating a family environment where Chess was fun. From the way it is described by Gladwell, there was more carrot and less stick, and so less conflict. I don't think the goal is to have to create geniuses, but rather learning how to instill a love of learning. It seems the Polgar experiment achieved that.
I suspect Stuart is right about allowing freedom being more appealing. The world is skewed to specialists at the moment, but perhaps the future belongs to creative individuals and being creative is about connecting the dots.