Why do we need a large userbase and minimal human moderators? That's a super rich-get-richer model that only works by abusing the platform/publisher divide, not a reasonable business model.
Five hundred thousand mom-and-pop grocery stores are a much healthier economy than Wal-Mart taking over everything and establishing a monopoly. Five hundred thousand well-moderated small forums, news media outlets, and messaging services will make for a healthier internet than Alphabet, Facebook, and Twitter establishing a cartel and controlling the message/mining everybody's data.