There was some decline in quality of life in the transition from hunter-gatherer life to early agricultural life, but there is still a huge gap between the quality of life in hunter-gatherer societies, or medieval agricultural societies, and modern societies.
SA was a society with small GDP that became wealthy through development of natural resources. Similarly Canada has a significant amount of resources. Colonial expropriation meant that these resources have not been controlled by the previous regimes.
[A] major source of income for the ruler of Hijaz was the taxes paid by pilgrims on their way to the holy cities. After the depression hit, the number of pilgrimages per year fell from 100,000 to below 40,000.[2] This hurt their economy greatly and they needed to find alternate sources of income. This caused Ibn Saud to get serious about the search for oil.
https://en.wikipedia.org/wiki/History_of_the_oil_industry_in...
Yes that is correct, and I see your point now.