Interesting seen this way.

Word of note though. Salaries are quiet spread out. The people likely to buy new iPhones are likely people earning top 1% of salaries in most countries in Africa.

If this viz is focusing on average salary, then it is a general description and should not be compared to other countries with different income spreads (min-max). It can be quite deceptive. Upper middle class in a place like Kenya or Myanmar live a far more better life overall than say lower middle class folk in the US.