You're getting downvoted because it seems like you're plugging a book and didn't actually say why you cringe at the word "gap" - your comment is pointless and contributes nothing.
It's certainly unrelated to the article, and the OP didn't understand why they received downvotes, so I believe my explanation was sufficient.
And it is absolutely related to the article. The very concept and terminology of "gap" is the first thing Rosling critiques in Factfulness, as a faulty way of thinking that misleads us and keeps us from seeing the truth about the state of the world.