What makes us think that that isn’t exactly what this is already?
Nobody really knows what the blobs do. They likely have paved the way for Stingrays and other devices.
If Apple really wanted to they could secure the iPhone. Just offer a 2x higher bug bounty than any government and things like stingray would not work.
Although I think recent iphone designs don’t give the modem DMA so it’s still better than Android but I wouldn’t consider it secure.