Yes, we do need this more now than ever.
It always struck me as strange that we had IM clients on our computers for so long, then there was this strange lag while we got something comparable on smartphones. Then when we did, it was like we started from scratch.
Regardless, I don't think it will happen. The world has gone notification-mad, there's barely an app (or website) out there that doesn't want to notify you of something. That's clearly because they need your attention to help monetize the platform (you are the product, after all). If messaging apps allow you to go "AFK", that's less interaction, meaning less $$$.
The harsh reality is - they don't make these things for us, they make them for them to make money. Unless it's likely to generate more cash, it'll never happen.
L8r.