> I’ve never heard of a single app where the off-app billing affected the inclusion of the app in the store.

most apps don't do payments like this to begin with.

>To be clear, I’m taking about the case where Patreon could decide to show no billing details or links at all in the App Store, just like eg Audible.

To be frank, I don't think Patreon has the same market force as Audible. Audible can definitely appeal to apple and make a deal that others don't get. Maybe Patreon did desire some of this, but I do put the blame on Apple. This is hardly the first time they arbiriarily played hardball.