Okay, I agree with everything you said but Medium would probably never show earnings in the stats page. The reason is:
It's not Medium. It's Apple!!
Essentially, every iOS app that's earning(or showing earnings to the users) needs to use Apple's in-app purchases--Apple Pay. Apple charges 30% for every purchase(yes they are monopolistic). A lot of apps like Netflix and Spotify suffered from it. Eventually, they bypassed it by asking users to sign-in on the website as they cannot mention monetization stuff on the app.
I think Medium doesn't show the MPP page, or our earning stats in the iOS app for the same reason(you'd notice when you click a stat, it opens a web page which is not bound to the app).
Now, if Medium thought of showing stats with earnings on the website, they'd probably have to do the same in the apps OR make it inconsistent which would require two different data sources--one for the website and the other for apps.
I believe that's why we'll never see much about money stuff in the stats. Dunno if what I wrote makes sense completely, but Medium's hands are tied w.r.t. apps