But humans aren't more productive for the most part. What had made people more productive is, for the most part, mechanization, computerization, and other tech tree improvements.
Even though everyone didn't get rich from the industrial revolution, ultimately people led easier lives, more stuff, and less work.
Peasants in the Middle Ages did hard, agrarian labor, had poor sanitation, high child mortality, and limited horizons. While nobles had wealth and comfort, the era was generally harsh, with most lacking modern amenities and facing short, physically demanding lives.
Even though everyone didn't get rich from the industrial revolution, ultimately people led easier lives, more stuff, and less work.