Today Android phones have this malware on them and iOS phones do not, so the actual facts in the real world are that iOS is free of this intrusion.
That might change, but the situation now is what it is. This is why you are getting downvoted.
We just don't have a sample to reverse-engineer yet.
Edit: when I wrote this comment, my original comment was at -4 points.
That’s all.
I mean, if you wanted a hidden, non-standard launchd type app, you'd have to modify the filesystem, install it, they'd need to create special tooling to do so, and modify the updaters to preserve it across an iOS update, etc. All without anyone at Apple speaking out.
Apple refused to create an unlock tool for the US government that was a one-off, to create spyware for China seems like they last thing they'd do. Could they? I guess. Once detected - and it definitely would be (as this was), or leaked by employees - Apple would get bowled over by buyers and the stock market. It's just not in their interests. Their current business model is selling privacy.
https://news.ycombinator.com/newsguidelines.html
These biases are in the eye of the beholder. People with opposite feelings about Apple (or whatever the corp of the moment is) see exactly the opposite bias.