I guess diaspora* is supposed to be the decentralized facebook replacement, but I don't think it's any good. I dare say that it's too late for even a good replacement to compete with facebook. Google tried while there was still time (and failed). But now? I don't think you can.
I think something like Opera Unite had the potential to be a single instance per person if that ever caught on.
Google hasn't had a great track record with these things in general. The problem with a lot of Facebook alternatives is that they make a somewhat better Facebook and then hope everyone will switch over. Of course that's going to fail. Sites that succeed have reasons for people to use them even if there aren't mass migrations.
We know that people have a need for social sites other than Facebook. Slack's been successful, so has Discourse. Heck, meetup.com is still going even though by a naive understanding of things Facebook should have subsumed it (it has a much smaller base, and you need to pay something like $140 a year if you want to start a group). A Facebook alternative will eventually catch on, but it's not going to be a site that starts out by trying to mimic Facebook with a few extra bells and whistles attached.
The people in the offices are too dumb to even grasp what servers are, let alone distributed services or why would standards be beneficial for the society. Maybe next generation knows better if we by then are not under the iron rule of few SV companies.
A charity? Sure, if you can make it work. But a public utility? That would link it to governments, which I think is the last thing we should be pushing. I think there is already enough concern over how Twitter interacts with governments, especially those looking to censor speech. https://en.wikipedia.org/wiki/Censorship_of_Twitter