"it's trivial to call Objective-C APIs from C or C++ code"





Agreed. But there are non-trivial performance costs. Just profile your app and see how much time objc_msgSend() eats. You realize method calls in Obj-c are dynamic dispatch, right? Same with properties. Just compiling obj-c with c/c++ is completely not the issue.





"in another language wouldn't magically give better real-world performance"





Yes, it can. Obj-C and C++ have some fundamentally different internals. People are asking this for real reasons, not for language religion. My desire is based on our own real on-device profiling data.





In our engine, we've resorted to making C++ shadow versions of some Metal api classes just to reduce costs on hot paths. I'll add another vote for a real native compiled API, but not expecting it to happen.