If I understand the graph correctly, the gap in absolute terms reduces, when the derivative of the (original) Elephant graph is negative, that is the gap between the lower half of the income distribution and the P50-60 (6th decile, something like $2k - $4k [0]) increases. And the gap between P80-90 ($8k-$14k, that's the lower third of the US population) and the top increases, while the gap between P50-60 and P80-90 decreases.

[0] https://ourworldindata.org/global-economic-inequality

specifically from eyeballing

https://ourworldindata.org/wp-content/uploads/2013/11/Global...