Yeah, it's obvious that resources of a country is were each of the country economy originated and if not properly handled by the management of the country,automatically the economy of such country will fall totally, so looking at the falling of countries economy from another perspective it seems that its caused by Lack's of diversifying resources or economy.
Yeah, it's clear that massive disease in a country can cause stability or downfall of economy such as corona virus and other numerous disease's.
What about the technology factor, have you forgotten that countries with technology will grow faster? perhaps technology is also the cause of economic growth or decline. If the government and society do not have technology in their country. I am sure the country will continue to be underdeveloped.