There are 2 parts indeed. Jailbroken - provides ability of root / non-sandbox interaction. Without it, each process is sandboxed: * you don't have access to o

There are 2 parts indeed. Jailbroken - provides ability of root / non-sandbox interaction. Without it, each process is sandboxed: * you don't have access to other files (you can have some ability to have shared folders but it's very scoped) * you can't do much IPC if I remember correctly. So you're capabilities are more limited. Even if those were not critical, X11 as an environment would be useless as you'd need to have it on each app you build because the AppStore requires pre-compiled or interpreted code. You're not allowed to have an app that download other apps...