The thread is not entirely facetious. Nutrition issues used to keep humans much smaller. Which aided survivability in famine time. Which was often every late winter/early spring. Large specimens tended to be leaders, but also had to somehow justify their much larger appropriation of foodstuffs.

Social cohesion and teamwork also aided survival on a smaller resource footprint. As a trivial example the 1920's 3-flat I'm sitting in was built in a season. Replicating all the detail in this structure today would be most likely a 3 year project - even though it would be power tools, not hand tools, deliveries by phone call, not by teams of horses, etc. We have lost even the idea of teamwork.
And I'm quite sure this bldg was produced with an order of magnitude less waste than construction sites generate now.