Other platforms have different communities and users. There is absolutely no facebook replacement at this time. Whether or not it'll continue to be used in 10 years is another question. To clarify, I use neither facebook* or twitter.
My point here is that you cannot solve a human and social problem from a technical standpoint. It doesn't matter how good your product is if no one uses it. Mastodon will never be a facebook replacement, etc.
* Aside from marketplace and local buy/sell groups.
Facebook itself probably doesn't believe this.