Comment by Dagger2

It was never going to be a clean cut, which is why we didn't design it for a clean cut and instead developed a bunch of approaches to transitioning to it that deal with the real-world problems of the transition.

What more do you want from it?

What could they have possibly done differently to make you happy with it?

> people who either worked for the likes of Google who were aching for a globally unique identifier per device

v6 doesn't give you globally unique device identifiers. Devices get IPs from the network in v6, just like they do in v4. You're either thinking of MAC addresses or perhaps things like HIP (https://datatracker.ietf.org/doc/html/rfc7401). I guess there is Mobile IPv6 which allows you to take your address to another network, but then there's also privacy extensions which prevent your machine from using the same IP for very long, so it's still not a unique identifier for your device.