Earlier quoted context omitted.
Thank you for taking the time to explain. Let me try to word things a little better: What is the percentage of US homes who are on an IPv6? What is the percentage of websites on IPv6? What are the number of web site hits that are IPv6 to IPv6? (in the US? in the world?) The highest estimate I've ever seen for any of these is less than 20%, which - 20 years into IPv6, is in my opinion "not caught on". The mobile world…
Giving a user the same IPv4 address on every connection is not uncommon either. It's a policy decision made by the provider, unrelated to IPv4/v6.
All local ISPs I've asked, don't give out the same IPv4 (they all charge for a fixed IP, so no guarantee you'll get the same one unless you pay; at least 3 out of the 6 actively change your IP whenever they can, to force you to pay even if you need fixed IPs for short times).
All local ISPs I've asked provide the same IPv6 prefix to a customer.
I assumed that was common practice - at the very least, more common than the other way around (fixed IPv4 when you didn't ask for it, random IPv6)