Epic is a great example. Their own store lists alternative stores on the Epic store, like itch.io. But they don't take a cut of games bought from those stores. Once you launch itch, you're in itch.
It'd be like if Apple took all of the developers who testified against Apple, reduced their commission to 0% in perpetuity, and then asked the judge to throw out their testimony because the complaints were moot.
(That being said, I do think there are conditions where stores would/should allow other stores, and I think those conditions could be more permissive than the Roblox example. Apple should, medium term, resolve the GeForce Now/XCloud objections.)
After playing that game, I saw promotions for Assassin's Creed Odyssey on Uplay, and purchased it. I later went on to purchase many other games on Uplay.
In short, Epic allows Ubisoft to sell games on its store, for which they presumably pay a cut - for those sales. But Epic has no problems letting Ubisoft require their store be installed for those games, and if you buy something there - even though the Epic Launcher installed it - they don't get a cut.
This is more akin to the App Store installing Fortnite - which Apple could get a cut out of, but not getting a cut for purchases in the app.
On the Apple side, it's ok for applications to require the user make an account on services like Uplay (I believe several Ubisoft games require this; and Fortnite requires the Epic equivalent). You can then use that account to buy stuff on the stores. It's not an exact parallel because there are no (non-jailbreak) external app stores on the iPhone, but it's a close parallel.
And Valve allows you to sell steam keys on your own website also without paying the cut, so long as you don't undercut the steam store.
https://www.reddit.com/r/pathofexile/comments/1ogbo7/will_mo...
Do you have any sources on how restrictive valve are or have been with that, or is that just speculation? Can developers default to their own payment systems and bypass valve's, or is theirs required to take a secondary, less-accessible option (when it's even allowed)?
From the same thread, the mtx cut taken was a dealbreaker for redfall studios, so it certainly sounds like they didnt get the option for their own mtx transaction service: https://www.reddit.com/r/pathofexile/comments/1ogbo7/will_mo...
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