Imo the author is missing crucial point, by making comparisons of things which are not comparable. You can not say, Person A is brilliant at xyz, why is Person B not brilliant at it, even though the circumstances and resources might be identical. The difference is, people who push themselves or are pushed to be good or great at something will barely come as far as those people who get drawn to something, because it means the can avoid suffering, grieve or else. Imo this is the strong driving force here, with the examples of Erdös and Ramanujan. I claim Ramanujan didn't became a great mathematician, because he wanted to be good at math, but mathematics gave him a space, where he could forget about his devastating circumstances of poverty and inequality. And the deeper he got into math the more he felt aligned to it and at home.