They would think we are so advanced in everything we do they would wanna become one of us
One of the main ways in which the population of Western Europe changed after the collapse of the Roman Empire is that it became more diverse, since the official borders of the Empire were no more. There was also increased lawlessness. <span />
Steel production decreased after ww2
People in the south used slaves because their economy was focussed on things like cash crops (tobacco, cotton, etc.) These crops required a lot of work so farmers and plantation owners could not do it by themselves. So by using enslave persons they could harvest more crops, sell more, make more money, and in return boost the southern economy.
They are at the top because they are the wealthiest and have to most authority