> offline-pretend-posted

It's a far, far more complicated mental model than simply posting it. It'd be a huge barrier for normal users (even tech-savvy users, I'd say). People want to post it online and that's it. No one wants an app what requires its users to be aware of syncing state constantly unless they really have no choice. We pretend we can step on gas instead of mixing the gas with air and ignite it with a spark plug until we need to change the damn plug.

Email clients had the outbox that was local only and then you pushed to send them all. Hiding the outbox is why some of these things seem fiddly to use, despite being conceptually very simple. This model would seem to work very well at least for non-collaborative changes like IG posts.