[gojomo]

And yet: something that bothers me about that book/movie is that its portrayal of the labor/immigration dynamics seems exactly backward.

Without a fresh supply of young workers, but with all the factories/tools/capital/housing that supported a larger population, the benefit of incremental workers becomes gigantic.

The winning regions in such a scenario would be those that welcome massive immigration to maintain production.

Even assuming some xenophobic fear arising from the uniqueness of the zero-fertility situation, nations like the UK or US, that already have the benefit of worldwide adoption of its language (and cultural exports), and functioning beachhead immigrant communities of all types, would in such a scenario be most likely to recognize that immigrants could soften the pains of a population-shortage.

Keeping immigrants out would require even more of the dwindling population wasted on 'guard labor', and even more empty buildings/communities and idle factories. And to the extent that there are culture clashes – there's now plenty of space to congregate in voluntarily-segregated communities, but still within the same national boundaries for easier trade.

So while I loved a lot about the 'Children of Men' story/movie, its economics were all wrong.