I strongly suspect Patreon is playing fast and loose with the wording here. Note they say “if creators on Patreon disable transactions…” but not “if Patreon were to disable all transactions.” I’m pretty sure they could still go the Audible route where they remove all mention and links to billing options off app. But Patreon doesn’t want to go that route across the board, they still want people to be able to sign up for things in app.