It's an interesting distinction, or if there should be one, between libraries-that-provide-value and libraries-that-must-be-used-to-access-a-platform.
If I create a platform, and an SDK that targets that platform, and require everyone to pay for the the SDK to use my platform...
... is that the same as if I create a set of libraries (nee game engine) that avoids you from having to recreate that work yourself?
I'd hazard that the two are different, because Epic isn't really gating access to an "Unreal Device" by withholding access to their engine.
A developer is free to use a competitor's engine and distribute the same places. (Afaik, Epic's store doesn't have any "must be built on Unreal" qualifier, right?)
It's absurd to argue that Apple's libraries don't provide value.
Apple's SDK includes the compiler that target's Apple's chips, a fully-featured IDE, the platform specific APIs (sure), the UI framework, a shader API, a physics engine, etc.
Are there alternatives to using Apple's SDK, if you want to target Apple's hardware, which has a substantial market share?
Limiting the ability for dominant companies to crown themselves gatekeepers and toll all who pass was the intent of the EU rules.
If Apple tries to argue that the one SDK is intrinsically tied to the hardware, and also conveniently is required for apps on any store... that starts to sound a lot like 90s Microsoft and Internet Explorer, except Apple doesn't have the "But it's free" defense.
I mean ultimately both companies have invested R&D into building their SDKs and it comes across as bizarre to me to suggest that one company should be legally banned from charging licensing fees for their use.
But if we've decided that it's unhealthy to allow dominant tech firms to tax everyone for access to their platforms...
Then an SDK might become the final area where they attempt to do so.
It'd certainly be a lot cleaner if there were 2 SDKs: a base, primitive-only freely licensed one with the bare minimum for interacting with all platform components and a higher-level, premium paid one that had better DX.
If I create a platform, and an SDK that targets that platform, and require everyone to pay for the the SDK to use my platform...
... is that the same as if I create a set of libraries (nee game engine) that avoids you from having to recreate that work yourself?
I'd hazard that the two are different, because Epic isn't really gating access to an "Unreal Device" by withholding access to their engine.
A developer is free to use a competitor's engine and distribute the same places. (Afaik, Epic's store doesn't have any "must be built on Unreal" qualifier, right?)