I think this goes to the fact that we need a new sort of UID. Something thought through very carefully rather that something that comes to be. There's a sort of hidden infrastructure, hidden legacy, hidden stability that's been built around phone numbers and email. For instance, "valid Google email address" is a proxy for "a real person with X likelihood". Same goes for SSN + demonstrated knowledge of your last few residences, etc etc. It's a mess.
Start from first principles, what do we really need to know about a person? What could we build? On the other hand, maybe if it's too good it'll be bad for privacy, and escaping into the shadows, should that become necessary for someone.
The question I think I'm getting at is about who you are and why that matters in a given case. Blockchains are good for keeping identities intact once established, which is different though maybe it'll help overall.
Start from first principles, what do we really need to know about a person? What could we build? On the other hand, maybe if it's too good it'll be bad for privacy, and escaping into the shadows, should that become necessary for someone.