Aside from what others have said which I agree with. Let’s go with the other rather blunt angle. It wouldn’t matter if the USA was called (insert made up word). Most of the world would still think of the USA and maybe Canada & Mexico because quite frankly the North American continent is way more dominant then the southern 1. Brazil is possibly the only other 1 that would spring to people’s mind. To be rather blunt those other countries aren’t really thought of because they are largely insignificant on the world stage. People don’t often know a lot about them because they just aren’t important enough on the world stage. It’s like how as ruler of a a county I don’t know the working of every small village. You can claim its ignorance but any reasonable person is just going to say how could they possibly be aware of everything.

At its base the world is currently centered most significantly on The USA. Other organizations and a few other other countries sit right up but the USA is pretty clearly in the number 1 spot when all things are considered. You may not like it but that’s largely how the world is right now. Overall other countries basically get to chose from China, Russia or western centric. The world seems western centric because a lot of countries prefer the western 1. They can choose none and some do but countries choose 1 because they like what comes with it/they want to be more like these powerful and well off areas.

The USA did come with a name and its the 1 we are using. It’s perfectly fair.