If Unity and Unreal Engine disappeared from iOS you'd probably lose at least 50% of the games on that platform, if not more. Likely almost all of the top revenue-generating titles. People use middleware like UE and Unity to compensate for how difficult it is to ship games on Apple's platforms (along with others) instead of building for Apple's SDK. The citadel demo is the tip of the iceberg.
Some seriously willful ignorance to pretend that a scriptable scenegraph is the same as a game engine. Netcode, entity systems, loading/streaming systems, matchmaking, achievements, level editors, material/shader editors, model editors, physics, particle systems, lighting, sounds, voice chat, plugin libraries/mods,... the game engine of today is a big thing, & well integrated.
Second, who would adopt a platform specific "game engine" like scenekit? Are you going to rebuild your whole game to port it, is that the plan here? Apple is categorically unable to compete with actual game engines exactly because they dig their own hole, invent their own proprietary closed technologies (metal, scenekit) up & down the stack. They aren't playing keep up with the real tools, a game of "me too": they can't begin to compete with the real deal even if they tried.
That's kind of the point. It makes it disingenuous when Apple says "everyone loves our SDKs, they're getting so much value out of them that a 30% cut is a bargain!" when everyone is papering over the APIs with a game engine and would be just as happy with a generic chipset vendor OpenGL ES implementation
The same kind of people that adopt platform specific game engines like PhyreEngine, and sign console exclusives.
Apple engines are so bad that Cocos2D-x is basically a copy of their features, using C++ instead of Objective-C/Swift, one of the engines that Google and Microsoft give first class on their platform SDKs.
Not every game engine needs to be a bullet point list copy of Unreal capabilities.
And no I am not joking, contrary to many here, I had a past life in demoscene, been a former IGDA member, previous GDCE attendee (London and Cologne), have been inside a couple of known AAA publishers and have kept my contacts from them.
You're right. It seems like a weird way to build to me, but I can confess to that being a bias. Plenty of people do opt to build to platforms, & adopt narrower tech. Go everyone, whatever you use.
