I thought the mound of vibranium was important to the story because it represents the gold and diamond mines that have enriched colonizers while keeping many of the African people in poverty. What if Europeans had never found those minerals? And what if the African nations had been able to use those resources for their own benefit instead?
Abundance of natural resources can be a curse as well as boon. Dependence upon a single form of commidity to fuel a society, whether by the natives or by conquerors, produces little difference in the negative consequence of such dependence. Even had the various African tribes and kingdoms could have monopolized diamonds or gold mines, over-reliance of such mineral deposit exploitation would have reduced these natives into economic colonial states.
As a historical example, consider Spain at her height, an empire where the sun never set. After three centuries of gold and silver mine exploitaion, and having transformed her society into essentially resource excavator/mining economy, Spain was and remains, one of the poorest nation-state in Europe. Much of the precious metals flowed directly onto Dutch, French, and English coffers, not due to pirate raids, but due to Spanish economic stagnations and dependence upon foreign imports.
It will be interesting how this plays out in the sequel (of course there will be a sequel). So far they seem to have relied mostly on keeping it for their own purposes. I'm not sure I recall how it ended up in Captain America's shield. Was that an export or part of the stolen vibranium?
Also Chinese and Indian coffers- huge portions of the gold and silver from the conquest of the New World went straight into the spice trade, since other than gold and silver, Europe had nothing the great eastern powers wanted at the time. It resulted in a severe shortage of specie in Europe for a long time.
Ooh, interesting perspective!