That's really interesting. I was just watching an episode of Adam Savage's Tested last night where he visits the MET. They were talking about armor that was being developed to protect soldiers fighting in the trenches. They ended up rejecting the design for the WW1 helmet because it "looked too much like the Germans'" When in reality, it's shaped that way to give the dome strength and provide protection to the eyes, ears, and neck. And both the German and American design borrowed from classic heavy armor designs.
https://m.youtube.com/watch?v=ZZfDNW3eOJo
They start talking about WW1 and 2 at about the 15:00 mark.