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)
Hans Rosling provides an exhaustive rebuttal to that question in Factfulness:
Here's a speech he gives on the topic:
To make it as short as possible: if you're concerned about family sizes, the best path forward is, counterintuitively, improving health and reducing infant mortality, not the opposite. Parents seem to compensate for high infant mortality and high poverty with larger families, but naturally adjust family sizes downward as conditions improve. That trend seems to hold in countries all around the world, dozens of examples so far without counterexamples. (I.e., Malthus was wrong, according to all the data we have.)
But his book is still really worth reading, it bolsters his argument with much more data.
Spoiler: The world is actually getting a lot better really fast.
If you're looking for a more global outlook on the longer term future, then this book is a great place. You can read it for free, per Bill Gates' donation to graduated of the class of 2018, here: https://archive.org/stream/FactfulnessByHansRosling/Factfuln...
I'd buy it for an easier reading experience here: https://www.amazon.com/Factfulness-Reasons-World-Things-Bett...
Here's a quick quiz for you to test if your knowledge of the world is better than a chimp's: http://forms.gapminder.org/s3/test-2018
That's correct - countries like Lesotho and Central African Republic are improving faster than his home country of Sweden ever did, at any time. In only his lifetime Sweden went from having an infant mortality rate similar to that of the poorest countries today, to being one of the world leaders. Those poor countries are improving faster than Sweden ever did... so in just one more lifetime they'll be where the world leaders are today.
The book makes it plainly clear that the world is improving much, much, much faster - even for the poorest - than the mainstream media would have anyone believe.
 https://amzn.to/2Ihb6jM - full title is great "Factfulness: Ten Reasons We're Wrong About the World--and Why Things Are Better Than You Think"
Whenever I read statements like that, it's as if somehow the EU/US think they have a right to be the dominant global economic and political power, and somehow it's their moral right to stop anyone else from ascending to that position.
China has over a billion people. So does India, so does the continent of Africa. They are all developing much, much faster than the vast majority of people realize 
Anyone who thinks the EU/US will remain the dominant global economic and political power in the next decades is severely deluded.
 Checkout the fantastic "Factfulness: Ten Reasons We're Wrong About the World--and Why Things Are Better Than You Think " by the master Hans Rosling, where he clearly demonstrates using irrefutable stats that the poorest countries in the world today are developing faster than for example Sweden ever did, at any point in history. https://amzn.to/2CXPdCu
The world is a lot different than many people think.
I highly recommend it.
 Factfulness: Ten Reasons We're Wrong About the World--and Why Things Are Better Than You Think - https://amzn.to/2CXPdCu
But you're in good company thinking that.
Fresh book recommendations delivered straight to your inbox every Thursday.