After Apple kicked Fortnite from the iOS store, there was an outcry of people who had previously spent money on it through Apple's in-app purchases and now wanted a refund.
Some of those users switched to playing Fortnite on a laptop or Android phone instead, but of course they were still using Sign in with Apple if they had originally created their account and paid for items on iOS. Apple is now locking out those users.
So I predict another wave of upset users, this time it'll be the people that purchased through Apple and were then attempting to play elsewhere.
Meanwhile, Epic now has a very good reason to collect a working email address from every past iOS customer, which they can immediately use to offer the customer a 20% rebate on future purchases if they buy directly through Epic and circumvent the Apple tax.
Plus as an added benefit, Japan has now started an antitrust investigation against Apple after various smaller Japanese game studios (most of them Unreal Engine customers) have come out in support of Epic: https://www.bloomberg.com/news/articles/2020-09-03/apple-app...
And lastly, the combination of pressure on Epic together with the looming iOS14 update have made iOS a lot less attractive for mobile game studios, most of whom traditionally used advertisements to subsidize free players: https://www.consumeracquisition.com/game-over-ios-14-idfa-lo...
I found this quote which I think is quite fitting: "As the folks at Microsoft used to say in the early days of the Xbox, developers are the canaries in the coal mine. When they start dying, the platform is in trouble."
https://venturebeat.com/2020/09/04/the-deanbeat-apple-must-t...