fun fact: comcast have been proactive about ipv6 because their management network grew so large and unwieldy, through various acquisitions and long term inefficient use of space, that ipv4 RFC1918 10/8 (and 192.168 etc) was no longer sufficient to address all of their individual netblocks.

turns out that if you allocate a private /24 to every POP you can absolutely exhaust 10/8 in a big last mile ISP.

they started with ipv6 for their own management network before any public netblocks started getting rolled out to customers.