> Any solution to the 4->6 transition that assumes that all devices of some class (be it clients, servers, or middleboxes) moved to IPv6 at once is deluded and would not work.
464xlat allows communication from ipv6 only clients to legacy ipv4 ones without the need for a separate stack on your end device
nat46 allows communication from a legacy v4 device to a modern v6 device without the need for a separate stack on your end device
Had ipv6 transition been thought about better back in the 90s then you could have deployed your new subnets as ipv6 only back in 2005 and still communicate with all your older kit.
> That thing is there to stay for 5-10 years, and you just work around it as best you can.
IPv6 is 30 years old. I sweat assets like there's no tomorrow but the oldest kit I've got active today is less than half that. Even for ipv4 only devices, a single legacy subnet would be reachable from my v6-only management devices via my ipv6 backbone via 464xlat