Discord isn't social media, it's an instant messaging app and a terrible one at that. A messaging app can't fully replace early-Facebook-like social network, because it just works so much differently and is optimized for different use cases. There's strangely nothing at all to fill this particular niche, although I'm working on one fediverse project that tries.
I find it hard to believe that there are no products out there trying to fill the 'early-Facebook-like social network' niche. People are discovering that a true social network, between actual people in the physical world, is not a scalable thing...and it should not be. On top of that, these same products trying to create social networks eventually run into a monetization problem.
