As long as Google ignores us or shoots down our solutions, likely no official youtube. (try the third party ones, they're quite good, and arguably superior to the official ones elsewhere)
We don't know what Snapchat's case is, I personally suspect they're holding out, hoping for a payday from MS.
etc etc, I don't know. There's always a chance. Heck, there's even a chance that Apple folds tomorrow. (hardly a noticeable one though)
But as for your "more apps" thing, of course. People develop and submit apps all the time.