Will it ever be possible that Google develops one messaging and video app instead of 9?
You mean like Google Hangouts used to be, before they butchered it? I'm still mad about that - it actually was the reason I bought my first iPhone. I no longer have a messaging system that does everything on Android, so I switched ecosystems for iMessage.
Or how Google talk was before hangouts. With talk, at least, you could use any XMPP client, and the web ui was wonderful for the time.