I think an interesting question would be if we could switch up the people. Insert the kid who grew up in a good home into an area with very little hope and opportunity, but with all the so called skills about hard work and nurturing. How far can he be expected to get having the right mindset but very little opportunity if he is born in the wrong country/city, born the wrong color, etc.? Likewise, take a kid from some God forgotten place and put him into a nice environment with opportunity.
I bet that if you repeat this experiment 100 times, you would arrive at a highly statistically significant result which shows that in the place of opportunity, your chances of success are so much better, no matter how underprivileged you started, than if you start with the right mindset, but get thrown into a hell hole.