[commandersaki]

I don't know the state of IPv6 on consumer devices, but I can imagine from an ISP point of view it's a massive support burden.

IPv6 excels on smartphone handsets since the telecom company has full control of your network/IP stack. Simple to support and manage.

However consider a home network situation, you have the consumer router, and attached to it is a bunch of devices, some which have iffy support for IPv6. They all speak IPv4 well. From an ISP perspective supporting IPv4 only makes sense because it still works and you can count on downstream devices in a home network to support it. With the impending depletion of public IPv4 addresses, ISPs can rely on CGNAT. Less burden.