Comment by Telaneo

I'm sure the vast majority of app developers are very much uninterested in leaving Apple's App Store if they have any interest in capturing an audience of any size, unless they themselves are a giant corp and have a Fortnite or similar on their hands.

However, the looming threat of that being possible, and Apple not being able to block it from happening, will hopefully prevent Apple from making the App Store experience worse than it needs to be, both from the user's perspective, and the publisher's perspective.