alt Hacker NewsI know. All these things were possible and completed for IPv6, but that's only part of the battle. The rest is making it easy for users at various levels to migrate. IPv6 didn't do that, that's why we're stuck in today's situation.
IPv6 added an unnecessary requirement to change all existing routes, which is huge. If still using old v4 addrs in v6, there should be no need to change DNS yet. You shouldn't need a different DNS or DHCP server, only one that supports both protocols (also shouldn't be forced to use SLAAC). V6 translation to/from v4 should be doable at any hop instead of relying on a flaky anycast relay. The later stage of migration should just be that people start using longer addresses given that both ends are v6 and DNS etc supports it then. Even still there should be no requirement for every hop along the route to be v6, only the ones that go deeper than /32 near the ends. But we got all these extra constraints because of ipv6 design decisions.
But v6 did most of what you're asking for there??
It has "IPv4-compatible IPv6 address"es: https://datatracker.ietf.org/doc/html/rfc2373#section-2.5.4, and then a way to get them over networks where not every hop supports v6: https://datatracker.ietf.org/doc/html/rfc2893#section-5. You don't need new DNS or DHCP to use these, or SLAAC. There's no anycast relay. They can go over v4 hops.
Why spend all this energy complaining about v6 not doing something that it did do?
> The later stage of migration should just be that people start using longer addresses given that both ends are v6 and DNS etc supports it then
It seems your only real problem is that you completely missed the early part of the transition. We've been in what you're calling the later stage for twenty or so years now.