Well, in many cases they simply do not have the access to technology which would otherwise help them to easily exploit their natural resources, so the have to invite other countries to exploit them for them or get massive debts to invest in their own technology, both of those situations can lead to unwanted results and further impoverishment of the African people.
Nothing stops African leaders to embark there people on massive technological training so that in near future those who got such training can come back and establish the technological hob in their different countries and train others. Apart from sending their people out to foreign land for such training, they could bargain with expatriates to train their people in their home soil. Such bargain should be in monetary value and not to give out their natural resources at a ludicrous numbers of years to the foreign companies. The issue is that of leadership
Debts or borrowing shouldn't hurt the future generations in Africa if utilized very well. To borrow for investment and proper capital investment is good and well monitored devoid of embezzlement or corruption but utilized for the purpose at which it is borrowed. If such cases if they are utilized, the repayment might even be from the benefit and proceed from the investment. The government can borrow to build bridges which toll may be collected, borrow to invest in agriculture, investment in power and electricity etc , all those would be returns in the future but when they borrow they embezzle it within themselves and the coup will persist because the people are looking on the military to savage them into another phase perhaps it could be better.
So you are saying that the bulk of the problem is mostly related to leadership, however you also need to keep in mind the culture of each individual country to realize that a strong leadership is not all.
For example, if a president is in power and he ends up being one who pushes forward to production and employment, he could still end up getting overtrown by the military or the civil society, because the culture of them are more favorable for corrupted officials and local leaders.
You put a disciplined Japanese as President in Niger and he will get overtrown because his values are too different from those of the population.
You put a corrupt African into a position of power in Japan and he will be likely discharged of his political power for crimes and corruption. If people do not recognize what it is good for them then a good leader won't be enough for them to progress and attract those professionals who left their motherland.
I feel leadership do not comprises of just one man it is a collective effort. Majority of the leaders that are overthrown have failed in their own rule of law. They rigged their elections, change constitution to go more tenure, embezzled money, they don't deliver on campaign promises etc. In-fact we clearly see civilian rule not democracy. Where they elevate themselves more than the people.
I think Africa has a lot to contend.