I’ve been collecting a list of arguments in favor of maintaining the status quo on iOS and I’ve yet to see anyone offer a good solution to these:
---- The problems with letting all apps advertise external payment systems:
• Someone may publish a free app to avoid paying anything to Apple, and then charge users [an asston of] money to ""unlock"" via an alternate payment system.
• Users may not be able to see a list of all in-app purchases (and their guaranteed prices) as they can on the App Store, without downloading the app.
• Sharing your payment details and other information with multiple entities, and having to continually trust each of them (e.g. to not abuse or leak).
• Confused users may clog up Apple's customer support with complaints related to third-party payment systems.
• Angry users may demand Apple to offer refunds for shit that was paid for via third-party payment systems.
---- The problems with allowing third-party app stores on iOS:
• How will iOS sandboxing be enforced for apps delivered via third-party stores? Will those apps still have to be submitted to and signed by Apple?
• Store apps would need the privilege to write binaries on your iPhone. How will that privilege be regulated to prevent abuse? e.g. what happens if a store starts writing malware?
• Users may sometimes have to wait longer for an app to update on one store than on others (as already happens on Steam vs GoG).
• Developers would no longer be assured that they will have access to literally all the users that iOS has, by publishing on just one store.
• You would have to submit to each store, wait for approval on each of them, update for each of them... to come close to the userbase that you can currently access by just publishing once on the App Store.
• Developers will no longer all play by the same rules. One store may allow some content while another may prohibit it.
• Controversial content like porn may still ultimately be bound by Apple's ruling on such matters, rendering moot the freedom of third-party stores in what kind of apps they may offer.
• iOS Parental Control and Screen Time restrictions may be ineffective on other stores (and browsers too if third-party rendering engines were allowed).
• If an app or game is exclusive to a store that a user isn't already using, they would have to create a new account and maintain an additional app just to access that one exclusive.
• Not all stores may be compatible with the iOS backup and restore system, or the APIs for app-thinning and on-demand resources.
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To resolve many of those issues, Apple would have to ultimately step in anyway.
The need for third-party stores is really not that great to offset the advantages offered by the current system.