Not exactly an answer but:

No joke, when I was 8 years old, my family left the China for the first time and then I saw some food item in a store in the Korean airport costing something like 15,000 of a currency, I was like holy shit are all foreigners this rich?

Then my dad told me its just a different currency, its actually just equivalent to something like $10 美金 “American Money” (USD)…

Which I also didn’t understand what it meant, before that incident, the Chinese Yuan / Renminbi was the only thing I knew of…

So for a while, its was just the adult’s weird magic numbers to me lol…

I think some people just never left their country before and never learned about stuff, maybe their parents are also ignorant and never taught them anything.

And the English Language Defaultism probably arises from it being widely taught and so many countries use it like Canada, UK, Australia… and lot of the colonized countries still retained it like India… and its the probably most commonly taught languahe in non-anglosphere countries… So, some English-speaking people just made a false assumption about the world…