The Big Mac Theory of Development from National Bureau of Economic Research argues that it is not the people but their location that decides their wealth, after adjusting for purchase power parity.

An employee in McDonald in India earns 1/3 of Big Macs per hour compared to similarly skilled employee in US who earns 3 Big Macs per hour. In this case all the other factors such as skills, education and technology in McDonald remain the same.

It is not limited to low-end jobs. Software engineers in India, when immigrated to US earned double after adjusting for purchasing power, than their peers in India with exactly same skill set and capability.

Skills and capabilities are not a contributing factor to wealth across countries.

The conclusion is developed countries can perhaps assist developing countries through relaxed immigration laws than generous aid. It is economically beneficial for both countries.