> Pen pots aren't a thing that most people are familiar with

Personally, no. Cognitively? We've been seeing quills and ink in children's stories for centuries. One doesn't have to have used a bubble level to get the analogy in the iOS Level app.

> pen and paper, but now a) everyone knows what a pen and paper look like

A quill and ink are conventionally portrayed in relation to writing. A pen and paper could refer to e.g. sketching.

I'm obviously nitpicking. But I reject the notion that we have to oversimplify to the degree you're suggesting.

> it literally says the name of the app

The OS does this almost everywhere apps exist. Putting the name in the logo is superfluous.