The trick is in that rotating part, I believe. IPv6 is large enough devices could (can/do) rotate regularly. Sure every device is a unique snowflake, but it becomes a snowflake in a blizzard. Things like advertisers are going want to bucket things quickly and so they are still just as likely to use something like /64 subnet as the first pass identifier and your PC and daughter's PC are going to be hundreds or thousands of data points per month in different IPv6 addresses under that subnet. The Pigeon Hole Principle applies at least as well in that case of subnet hashing as NAT44 does. They are going to start with a "bucket" (your subnet) that resembles your whole household, and then filter from there.

The related flip side, though is that NAT44 isn't a privacy solution, it's an over-reliance on the Pigeon Hole Principle and hoping that's enough privacy. An advertiser already has way more data to work with than just IP Address: os/browser combos, user agent strings, cookies, timing habits (device hits website x first thing in the morning), and so much more. NAT44 is absolutely not sufficient for privacy. It is a defense in depth sure, but huge scale difference of IPv6 is a different defense in depth with similar Pigeon Hole Principle properties, it's not necessarily a loss of depth on its own.