This is an interesting idea. Say, on first boot of your new iPhone, you get a screen that says, "Which experience do you want?" with options, "Apple's curated"

This is an interesting idea. Say, on first boot of your new iPhone, you get a screen that says, "Which experience do you want?" with options, "Apple's curated" or "Choose your own adventure" with the proper caveats for the latter: "Choosing this option will allow you to install 3rd party software not reviewed by Apple. Such software could contain features which could harm your device. Some award-winning features designed by Apple will be unavailable in this mode. You may revert to the "Apple Curated Experience" at any time by navigating to Settings -> General -> My Experience." In other words, keep the walled garden, but give your users a key to the gate. The question is, will we then see users demand Apple make their software available outside the gate? I would want Apple to make no commitments to developing there. No Music.app, no iCloud, no iMessages, no Safari. You get a 3rd party store with 3rd party apps on Apple's hardware.