The problem is that windows was deceptive. Most african countires had no actual educated labor force to even began to build with.When India gained independence in the 1940s, it was an extremely poor country, around 80% of the population lived in poverty, struggling with basic necessities like food and energy. One of their biggest challenges was the energy crisis, which they tried to address by investing in nuclear power. However, even today, nuclear energy only accounts for about 3.3% of their energy mix, and much of the rural energy economy has long relied on traditional sources like cow dung.
I think the point about Sub-Saharan Africa’s GDP per capita was meant to suggest that there was a window of opportunity for growth, development, or investment but it may not have been fully capitalized on.
You cant really compare that with india or china which had a large class of educated bureaucrats to work with. The first generation of educated modern African elites only emerged around ww2 in the 1940s this was about 50 years after it emerged in china and India.
To be clear here we are not talking about the masses but the elite classes.