You listed the obvious problems, and imo the solutions aren’t as complicated as they make it seem. If a nation wants to build its economy, the first step is look at the countries that have a stable economy as a model. Their healthcare, access to quality education e.t.c.
My country is rich in oil yet one of the poorest nations in the world.
The development of a nation always comes down to good leadership. The resources might be available, natural and human resource but, once you haven’t got leaders that are visionary, leaders with the mind to build and make better, it’s always going to end in ruins.
Certainly there is always more to this than it meets the eyes, the politics that was instilled through colonization, puppet and puppet master leaderships and one of the worst of all is the national debt that remains a controlling factor on many nations. Where you’ll find certain nations having to sell their rights to generating revenue through using certain national assets as collateral.
The wealth gap is always going to increase and it would take a highly innovative leader to cut right between and narrow the gap.