If your ISP issues an IPv6 address, isn't that pretty much game over for anonymity/uniqueness?
Not usually, if you're comparing it to IPv4. Many ISPs give each customer a persistent IPv4 address that doesn't tend to change over time. Because most people use NAT (internal IP address != external IP address), a server you connect to can't identify the specific computer or device. With IPv6, it's true that in many cases servers will see you as connecting from the specific IPv6 address of your computer/device. Howe…
>So in many cases, the ability for a server to individually fingerprint your device solely based on the IP address is roughly equivalent between IPv4 and IPv6.
That still makes ipv6 strictly worse, if you consider that a device is always uniquely identifiable at any given time, whereas with ipv4 NAT they can't be individually identified.