In theory, we can. However, building a well-working multi-platform chat client is a significant task, imagine a 5-10 person team working over a year, plus the l

In theory, we can. However, building a well-working multi-platform chat client is a significant task, imagine a 5-10 person team working over a year, plus the long-term maintenance support. IRC might not be the right protocol for that, because you'll be adding quirks on top of quirks, but you could easily do that with XMPP. However, you won't find anyone willing to sponsor that development. Old protocols like IRC and XMPP just don't cut it in Silicon Valley. Examples for creating a new IM solution out of nothing, provided funding, include Signal and Matrix/Riot.