Why are you using the straw man graph for your curve you're addressing?

Where's the top quartile drop relative to measured performance?

D-K effect wasn't only around low competence overestimation but regression to the ~80% mean on both sides.

"It’s worth noting that the 'Dunning-Kruger curve' never appeared in the original paper and is basically a meme based on a misunderstanding(?) of the effect. Nevertheless, it resonates with a lot of people."