Edit: if you care to read more or donate, check these out http://www.zanaafrica.org https://www.huruinternational.org
It gives a much clearer perspective on how people live (and as you mentioned, how similarly people live across the world amongst the same income levels)
[0]: https://www.gapminder.org/topics/four-income-levels/ [1]: https://www.amazon.com/Factfulness-Reasons-World-Things-Bett...
> The three-world model arose during the Cold War to define countries aligned with NATO (the First World), the Eastern Bloc (the Second World, although this term was less used), or neither (the Third World). Strictly speaking, "Third World" was a political, rather than an economic, grouping.