WW1 really was a different story. The US adopted the standards of its allies when possible, or otherwise just couldn’t use stuff from their allies. We produced things for our own use, but not for everyone on our side of the conflict. Plus WW1 was kind of a massive resource pit for everyone involved bc of trench warfare.

The fact that we couldnt share resources among allies is part of where the push for adopting a standard came from. And the reason it ultimately became the US’s standard is because the US production was removed from the conflict. Meanwhile European factories were getting bombed. Before the adoption of our standards, our allies were actually paying to establish factories in the US that would build to European standards