You are conspicuously not noting how much Apple value the $89 billion they made on app store commissions last year.
What you are really trying to say is that Apple doesn't actually believe the security model is important, instead it's just about collecting money from the App Store, that's a valid interpretation, I just believe that Apple values the iPhone's long-term popularity higher than it values the short-term profits from the App Store. The fact that they can have both is mighty convenient for Apple.
The TAM is saturated. Taking share from Android is difficult. Making more humans use smartphones is difficult. Making more humans is difficult. Extracting more rent is not. So the idea that the security is more important for future revenues than the ability to exploit the userbase doesn't hold up, particularly when there isn't and can't be an alternative with a different security model.
If your argument is a more open model than Apple currently has for the iPhone that might be good argument. But I was replying specifically to the authors comparison to the Mac. My point is that Apple believes having a Mac-like security model for the iPhone would make it less successful, as evidence by there aggressive push to make Mac security more iPhone-like, without enforcing iPhone-style revenue sharing (e.g., you can buy and download software from anywhere without giving Apple a cent).