IOS was built from the ground to handle cellular networking, and the whole stack is optimized for that, including sandboxing network connections and not allowing server type applications or anything that directly tries to mess with the networking layer in a way that is not explicitly authorized.

Coming from a mature OS built from a completely different paradigm is going to require a lot more effort. In particular macos has a whole legacy of programs doing almost whatever they want.

Apple _can_ just slap a cell networking subsystem in it and let it crash and burn whenever something unexpected happens or the user gets out of the defined boundaries of when it should work (like depleting system memory), but that doesn't sound like a great brand strategy to me and is not what people seem to be expecting. Microsoft will be on board with it, but I don't see Apple.