What happens to the population is incidental. In fact, what happens to economic growth is incidental. You get a lot of excited talk about how wonderful the economic record has been in the last 25 years. It's total nonsense. Working hours are going way up.
Benefits are down.
Although growth has slowed there is highly concentrated profit. In the Third World the growth rate in the 1990s is about half what it was in the 1970s. That's one of the effects of one particular form of globalisation, traceable in substantial measure to the financial liberalisation. These changes in the last 25 years have had the effect of harming the international economy. It still grows, but not like before.