>Having a unified identity guarantees that people are held accountable for what they say, it reduces fraud, trolling, and it means people have 'skin in the game' when participating in a social environment, it's the basis for trust.

No, it doesn't. People are perfectly willing to troll under their real name. When Youtube forced people's G+ accounts to merge into their comments and people suddenly found themselves commenting under their real names, it stopped the trolling and hate... for like a week.

Hell, plenty of people on Usenet were assholes with their real names and emails in their signatures.