It's not really the same thing, as far as I'm concerned. I use both Matrix and IRC, very extensively.
Matrix is, for me, a replacement (or a slightly less annoying way) to handle "person to person and local group" communications. And the bridges beat having to run a bunch of other clients for Google Chat, Signal, etc. However, my goal there is to move people onto Matrix, and I've done a decent job of it so far in my circles.
IRC is "professional technical chatter during work hours," and I use it as such - as I've used it for the bulk of three decades at this point. There's some social stuff there, but it's mostly "deeply technical conversations in the sort of chat rooms filled with people there for the same reasons." It's very much been a bit of a superpower - build relationships in the right IRC servers and you have a massive "external brain" of relationships you can query for weird questions. I worked at a small IT shop for a while, and people eventually figured out the correlation between "An absolutely off the walls question" and "the clattery keyboard," when I started discussing the problem in IRC.
I don't want IRC to be Matrix, any more than I want to bridge "professional chat rooms" into my evening hours (which more and more are simply hard analog, offline, etc).