< rant > ipv6 was designed at a time where the internet futurists/idealists had disdain for operators and vendors, and thought we were evil money grabbers who had to be brought under control. the specs as originally RFCed by the ietf is very telling. for your amusement, take a look at rfc 2450. it took five years of war to get rid of the tla/sla crap. and look at the /64 religion today[0]. real compatibility with ipv4 was disdained. the transition plan was dual stack and v4 would go away in a handful of years. the 93 transition mechanisms were desperate add-ons when v4 did not go away. and dual stack does not scale, as it requires v4 space proportional to deployed v6 space. we are left to make the mess work for the users, while being excoriated for not doing it quickly or well enough, and for trying to make ends meet financially. randy, trying to deal with the mess since the early '90s --- [0] https://datatracker.ietf.org/doc/html/draft-bourbaki-6man-classless-ipv6-05