And then if you get sued you point at your own prior art. You don't need to patent something to prove you invented it, you just have to publish your invention.

At any rate, historically Apple has been aggressive in its use of patents, so even were that necessary it's unlikely that'd be the main motivator for them.

And so the circle is complete. From patenting something because it's not obvious to so things being so obvious we'd better patent them.

Is there a good reason to assume this would only be used defensively?