This should put another nail in the coffin of the idea anyhow:
The study gathered crude information on the state of technological development in various parts of the world in 1000 B.C.; around the birth of Jesus; and in A.D. 1500. It then compared these measures to per capita income today.
As it turns out, technology in A.D. 1500 is an extraordinarily reliable predictor of wealth today.
In other words the reason some countries are more developed than others today is because they were more developed yesterday. Trying to explain differences that go back thousands of years by using factors that only apply for 10s or 100s of years is inadequate.