> so no, diversity is not strong in the long run if it makes its citizens stupid by wasting all of the intelligence genes that have been selected for so far. intelligence is genetic, and wasting it is against evolution, no matter how much short-term power you gain during the process. that's all well and good, but had rome not incorporated its conquered territories, it would either be unable to expand altogether, or it would have to genocide literally everyone in these territories. the former would have made rome is an irrelevant shithole never expanding beyond central italy. the latter would have turned the entire world against them. rome expanded in large part by buying people off. rome, like all empires, was built on trade. which is also why they wanted to destroy carthage, which was their chief trading rival in the mediterranean. rome used the profits of trade to buy people off. the empire collapsed when rome couldn't afford to buy anyone off. they stopped paying the germanics/goths and the goths sacked rome.
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