I lived with less than $2 a day. The average salary in the country was less than $100 and this was in Eastern Europe, not in Africa. What changes the story completely is that the exchange rate makes all the difference in my case: we all had a fairly regular life, but the exchange rate was showing a very dark picture. Yes, we were not able to buy American cars in dollars, but a local built Renault copy was a few thousands dollars new. All the prices were extremely low in dollars, but meaningful in local currency. We had not just the basics (food, electricity, house), but an almost normal life.
25 years later, the average salary is more than 10 times more, in US dollars only. An iPhone is now 10 times cheaper, but the price structure is more or less the same and nothing changed, just the exchange rate. The food is 10 times more expensive in dollars, rent is 10 times more, the few things that are more expensive today in local currency are the ones that are heavily taxed, like gas and tobacco.