There's tons of alternate social media out there. Forums, Subreddits, Tildes, Discourse, Matrix, IRC, Mastodon, Lemmy, Usenet, and on and on. The truth is the S in SNS is always what social networks have been about.
IRC failed in technical side due to the failure in committee development model around IRCv3, Reddit succeeded by sole social factor despite being a carbon copy of Digg. To me, Bluesky vs Mastodon, and also Twitter vs Mastodon situations seems closer to the latter, even with controversial waitlist and the big turmoil, respectively.
I don't understand why so many technical people equate monopoly with success. I use IRC every day.
I actually like that IRC is less 'noisey' then most social media (I generally only hang on a few low volume channels) with no 'feed' being shoved at me, no algorithm deciding what I 'should' see. I bop into more popular channels as needed, but for general use, I find the self-directed nature of IRC to be the 'perfect social media' for me...eg I see only what I'm interested in.