Put Fortnite into a box and put it on the shelf at a store which will take 30% in margin on that sale (probably more). Should that store also be forced to allow buyers to purchase it off their store shelf through a payment to someone else? Of course not.
It's payment in-app that are the issue, not payments to the store. Apple played no role in generating these in-app payments, and shouldn't have the right to mandate use of its payment solution. If you bought Fortnite at a store, would the store get money over purchases made later inside the Fortnite application? Of course not.
