And the ability to view multiple channels / chats at the same time, please, for the love of productivity.

How has this been omitted for so long? I used to be able to have multiple IRC channels open at the same time. Now, gotta switch back and forth on that slow Slack UI.

Well that's of course in terms of features an duser experience, but these don't ensure your product actually wins in the market.

You don't need to win the market if the market has billions of users. Keybase has a few million users, doesn't it? Get 40% of that to use it, and you win.