I faced the same problem with IRC that I am facing with Signal today. Though this analogy doesn't really seem that coherent but I hope you see where I am coming from. No one I would like to communicate with via such apps/platforms seems to use it. IRC is great but I would like to connect it with people I know, are part of something I like or do, or are from the place I belong to. They don't. They have moved to other platforms, long back, or never really used IRC.
I believe a lot of existing IRC users, including me, are still around just because of the nostalgia.