[rattlesnakedave]

Would facebook still distribute through the app store (that enforces these conditions) if they provided an open platform?

Of course not. An open platform would decrease Apple's ability to enforce measures like this, and would be detrimental to my experience as a user.

[fartcannon]

If iOS was truly open, you could run that app in a container like you could on a non-locked down computer. Open is the best of all worlds.