I love this film and at a certain level, it is plausible (and even natural) that in times of existential fear, societies lash out against outsiders/immigrants.

I love this film and at a certain level, it is plausible (and even natural) that in times of existential fear, societies lash out against outsiders/immigrants. And yet I have economic quibbles! In an actual fertility collapse, a highly-developed country like the UK would have an immense surplus of infrastructure, housing, machinery, etc – capital – compared to the dwindling number of new, young workers. Immigrants (of all ages, cultures, and skill levels) could become incredibly economically valuable. In comparison, reliable 'guard labor' to try to hunt and confine immigrants would become very expensive. Compare, for example, the depopulation of the 'Black Death' in Europe in the 1300's. For those who survived, wages and opportunity grew, and attempts to enforce older rules which bound people to undesirable situations collapsed. Wikipedia suggests that "[p]lague brought an eventual end of Serfdom in Western Europe": https://en.wikipedia.org/wiki/Consequences_of_the_Black_Death#Impact_on_peasants https://en.wikipedia.org/wiki/Consequences_of_the_Black_Deat...