The problem with identifying such people is that we can usually point to some tangible cause of failure. I think it's more useful to analyze the traits common to most successful people:
* Not being born into extreme poverty
* Having a basic education (not many successful illiterate people)
* Having access to at least one strong connection
* Having "true grit", whatever that means
* Discovering an available niche
I agree with the premise that not being born into extreme poverty and having a strong connection within the activity/field that successful people are in are important. To me it just seems like if you don't have to worry about how you are going to survive at a basic level, it allows one the freedom to to explore higher order activities.
The article doesn't seem to do the author as much of a favor as the Freakonomics podcast she was just on, she seems to be describing that there is not necessarily true grit, that it has a lot to do with a person's relationship to the activity on many levels.