Look at pictures of people in their 30s back in the 70s, and compare them to people in their 30s today. It’s a massive difference, I hypothesize that it’s the leaded gasoline and secondhand smoke that makes it although I’m not aware of any science to back that up.
Treantmonk is a guy who does in-depth D&D math, I’ve been playing that game using his ideas for like two decades now and his channel is called Treantmonk’s Temple