You're entitled to your preferences, but "far superior... in every way" is a bit hyperbolic. In practice, with email, usage patterns vary wildly (forward, reply, reply-all, cc, bcc). IME Slack channels are cleaner and provide several benefits. Not just the option for ~realtime / synchronous chat (where email doesn't work at all), but the mechanisms for tagging users and other channels; "pinning" key attachments; all its 3rd party integrations (ie, it's viable as a "hub" for communications and record-keeping thereof)... Don't get me wrong; it's far from perfect, and email -- when used properly -- has substantial strengths. But so does Slack. An open-source, self-hosted Slack clone would be my strong preference.