On the flip side, successful startups that aren't full social but do require some authenticity verification have already been proven: nextdoor and blind, for example
I think the biggest issue is scaling to a facebook-style, reddit-style, or twitter-style "full-world" social network implies colliding people who have no other relationship or interaction but are linked through a topic or shared interest
And, in my opinion, when you hit a certain level of scale, the verification almost becomes pointless: there's enough loud angry and troll people out there that I dont think it matters if they're verified or not. You can't moderate away toxicity in discussions that include literally a million participants.
I think you need both verification and some way to keep all the users' subnetworks small enough that it isn't toxic or chilling. But then you lose that addictive feed of endless content that links people to reddit or Facebook or Instagram. Tough problem