Possible misleading title. Apple wants 30% of earnings, not “creator” earnings.
"In writing and over the phone, we explained to Apple that we could pay them 30% of our revenues (from our 10% take rate). It'll be harder to cover costs and build features as a startup, but at least it'd be coming from us. Apple insisted on taking 30% of creators' total earnings."
So instead of the creator getting $90 and the app getting $10 when someone pays $100 through Fanhouse, Apple gets $30, the app gets $7 and the creator gets $63.
Because of the nature of the app, the earnings in-app, which Apple wants, are creator earnings.
Your suggested title would be less specific to the point of being flat out wrong if Fanhouse makes earnings elsewhere... which they do.