… is from page 280 of Kristian Niemietz’s 2019 book, Socialism: The Failed Idea That Never Dies (original emphasis; reference deleted):
Before the advent of industrial capitalism, virtually the whole of the world’s population lived in abject poverty. Before the mid nineteenth century, it would not even have made sense to measure poverty, because such a measure would not have shown anything interesting. Its long-term average would have been close to 100 per cent, and it would only have shown random fluctuations, not a systematic trend over time. It is not a coincidence that poverty measurement started in Britain in the late nineteenth century. Britain had reached a stage of development at which poverty was no longer the norm and no longer static. Later, other countries went through the same process, when and to the extent that they embraced free markets.
DBx: Do not forget that the title of Adam Smith’s 1776 book is not An Inquiry Into the Nature and Causes of the Poverty of Nations; it’s An Inquiry Into the Nature and Causes of the Wealth of Nations. As I first heard it said by the late Peter Bauer, poverty has no causes; wealth has causes.