I'm confused, I grew up in the USA and for global maps the US was never centered. It was always on the left, like every map here:
https://commons.wikimedia.org/wiki/Maps_of_the_world , and Africa is in the middle. If the Americas were centered on a world map you'd have to cut Asia in half, with it being on both the far left and right. It makes a lot more sense to make the split in the middle of the Pacific ocean and that's how I've always seen it done, I can't even picture a world map with the Americas in the middle. Is this a misunderstanding?