People's estimates are informed by what they pick up (even subconsciously) from (social) media, books, movies, etc. And then they support initiatives/NGOs/government actions based on those beliefs.

Gapminder is an attempt to show how outdated our view of the world are. The first time I had come across Rosling's TED talk (see my other comment), it did strike me how little I had actively looked into the state of the world and how the state is more optimistic than one can conclude from doomscrolling [0].

[0] https://en.wikipedia.org/wiki/Doomscrolling