It's a shame that IRC usage is dwindling especially in techie circles. However I can understand it if it doesn't work for them any more although in my opinion IRC has a lot of moderation tools available. In any case, the "problem", of sorts, is not abandoning IRC but what comes next. The web is choke full of proprietary communication protocols that cannot talk to each other and you have private entities acting as gateways to online communication. Instead on relying on protocols and let clients decide how they connect to the network you have users being herded into walled "communication" gardens. This goes beyond Slack or Discord or chat-app-of-the-month. Having a flagship open-source project behind a proprietary platform for communicating with the users and developers can't help but leave a sour taste in the mouth.
Well, at least there is still Matrix to hope for.