[thrown_22]

It's not an argument it's a fact that the rich had more surviving children than the poor. Repeat for 5 generations and you have completely replaced the original population with the offspring of the top 10%. That's a century. The middle ages lasted 8 centuries.

That a simple mathematical fact like that is considered eugenics is reality denial on par with the flat earth society.

The 19th century was special because people figured out how to use coal to do the work done by muscle in the middle ages. The previous centuries had seen a continued decline in capital costs. E.g. mediaeval interest rates were routinely 15% and more for secured loans.