At some point, people merely adopted these platforms, transitioning from nothing to something. The notion that we can't simply transition from Facebook to nothing is nonsense.
Facebook free for 6 years and I find no reason to have it. At most when Facebook loyals use it to organize events. And I find it about those through actually seeing people. Plus I love shocking people with "yeah I don't use that crap" to see how they react. Maybe given recent events they will react differently?