**Do you really believe that Angola or Venezuela would become economic powerhouses if their Catholics just became Episcopals or Presbyterians?**
Once upon a time South Africa was a prosperous, peaceful nation. The religion of the country was Dutch Reformed, who were the continental cousins of the Presbyterians.
Yes, once upon a time South Africa and Rhodesia (Zimbabwe) were prosperous nations. This had nothing to do with the religion of those who ran it and everything to do with the fact that they were once run by Europeans and are now run by Africans. Many of those Africans converted to the same Protestant faith as the Brits and Dutch who once ran their countries. The conversions really didn't do them very much good.