A Social Network is Only as Good as the People in it
It doesn't matter if that network is on Facebook, Twitter, Instagram, LinkedIn, Mastodon, Reddit, online forums, etc... If the people who are important to you are not in it, then you'll find that it is not as good as you expect it to be.
This is easy to test too. Just join a social network/platform that is supposedly really good, but make sure it is a network where your important people are not in it. Use it for some time and you'll come to see, it's missing something. That something are your friends and family members who are not part of the network.
So to me, it doesn't matter if people can come up with a better version of Facebook or Twitter or whatever. What matters is if you can convince the important people in my life to to join your new social network/platform. Because at the end of the day, a social network is only as good as the people in it.