@ OP,
(I'm going to presume you mean Subsaharan Africa only). You raise valid points but problem with your argument is too one sided. For example the idea of a nation state is quite alien to Africans, this was imposed on them by their European colonial masters. Also a lot of the ex colonies are still quite recipient to their former colonial masters influence. Ivory Coast/France, Sierra Leone/Britain etc. And Africa wasn't developed for the benefits of Africans, it was developed for the benefit of European nations which benefitted tremendously from exploiting Africa.
Africa hasn't destroyed itself in the same way Europe did during the World Wars and also while it has recieved a lot of aid, it can't compare to the Marshall Aid Europe got straight after the end of WW2. Also the loans it recieved had high interest rates attached and the people suffered while the Dictators who borrowed the money lived in a life of luxury. It was very irresponsible lending done on purpose by Western institutions to make a killing on interest rates even though the people of the country had nothing to do with it. Normally if a bad debt has occurred it's up to the individual to pay it back or declare bankruptcy not his friends or family etc. But in African dictarshops, the Dictator would borrow money from the World Bank, then default, so the IMF would come in and say right since you can't pay it back we will lend you money but on the conditions you accept the high interest rates and cut back on public services in your country, increase your own interest rates and taxes and pay us back on time using your taxpayers money otherwise we will keep charging you penalties and your debt will increase and be made worse. And to make matters even worse they would force Corporation tax down and leave the country to even more exploitation.
Also in order to gain independence, Africa either had to fight for it which proved costly or there were a lot of conditions attached such as taking on the debt of their former colonial masters. Furthermore after the end of WW2 Europe wasn't really in a position to keep it's former colonies, it might have made it worse. And being colonised meant Africa counldn't go through an industrial revolution like Europe did they wouldn't be allowed to.
