Most systems when they are disrupted, tend to go on the extreme opposite end, will be extremely unstable, and then find a new norm.
Historically, the famous french revolution though it was the rise of the peasants against the bourgeois, it wasn’t stable till it founds its norm with Nepolean. Napolean wasn’t exactly an average citizen, but having been part of the revolution, he knew how to balance both worlds.
The revolution against Windows, gave linux, but it was not Linux but MacOS which won in the end.
Similarly the disruption against Amazon, wasn’t open platforms like ebay or craigslist, but shopify.
The disruption against the organized hotel industry wasn’t couch-surfing, it was Airbnb.
The disruption against the unionized cab companies wasn't Lyft or the umpteen number of ride-sharing and pick up a friend app, but Uber.
Change is constant — but when end-users and consumers say they want different, they mean one step to the right or the left, It's never all the way. What the majority of folks want is stability and peace of mind. That doesn’t happen in either of the extremes.
So when you see a system having built its fort in one end, and the opposite to it emerging, think what the middle would look like.
That’s where a Facebook alternative would emerge.