Relay.js is a user friendly IRC client, see http://relayjs.jit.su/ for a demo. Converse.js (https://conversejs.org/) is an XMPP web client that supports XMPP conference rooms. So I'd say we already have good, nice-looking clients and there's room for improving integration on a single service to reach for the masses.
Unfortunately, Relay.js seems to not support colors in IRC, i.e. the "^C3i'm green^C" mIRC encoding. But it looks sweet though, and if one could just skip the "type the server and channel name" (i.e. embed on a community website), it would pretty much mimic the chat experience, only better :).
Anyway, so even if we have examples of pretty, somewhat simple and good enough XMPP/IRC clients, the next step is to get them to the world at large. That pretty much leaves marketing to focus on.
EDIT:
Somebody should bundle a pre-configured IRC server and a webserver hosting Relay.js into a Docker/Sandstorm (https://sandstorm.io/) container set and give it/sell it to companies as "awesome internal collaboration facilitator that improves communication and helps empower the teams to build products for the next generation of the web", or sth.
