"A narrator explains that natural selection is indifferent to intelligence, so that in a society in which intelligence is systematically debased, stupid people easily out-breed the intelligent, creating, over the course of five centuries, an irremediably dysfunctional society".

I am seeing this happening is Thailand. The large underclass breed like rabbits, have minimal schooling, and then go on to breed like rabbits. So the cycle spirals ever downward. It explains how an economic despot like Thaksin can economically gut a country with a smile on his face, and still get a local audience even though he is in exile as a convicted criminal. What is that tourism motif, 'Amazing Thailand'. For sure.