This also happened in my country, Indonesia. In fact, recently one important person was arrested on suspicion of corruption. And the amount of money he corrupted was truly a very large amount. In fact, if the amount he corrupted was distributed to all Indonesian people, it would be enough to make all families have large capital and would be helped economically. And the corruption seems to have been carried out by only one person. And I imagine that there are many more perpetrators of corruption out there who are making all people in various countries, including Indonesia and Nigeria, experience economic difficulties as is currently happening. It seems that if a country can be free from corruption then that country can become a fairly rich country and the people will be prosperous.
In my opinion, the failures of a nation apart from the problem of corruption are:
1. Domination of super rich people (3% of top bankers in the world) in crucial economic sectors in every nation.
2. Through banks they make a country entangled in a debt trap that will never be resolved.
3. Through the dollar, they control the world monetary system complete with its tools (swift system)
4. Through the stock market, control many strategic businesses (state-owned enterprises in various countries)
There is a system that makes/manages us according to what the system owner wants