I assume you mean on an open hardware platform, because underneath Apple's SDKs are just more Apple APIs until you get to Apple's IPC interfaces to talk to Apple-designed hardware register interfaces.

Unfortunately when it comes to technology licensing, it is rarely successful to say you should pay less because you purposely made your job harder.

> Nowadays with LLMs people could probably patch up some FOSS SDK that perfectly replicates the original's functionality without infringing Apple's copyrights.

I don't intend to insult you, but as an iOS developer myself I have serious doubts about whether you have any expertise in the subject you're talking about here.