I've more or less come to the conclusion that the people who think v6 is bad don't know what they're talking about. If none of these people can come up with a better approach than v6, that suggests that v6 really is more or less the best approach available.

> after almost 3 decades and so much the adoption at 50%

I think we all wish it had been faster, but the v4->v6 transition is the first time humanity has ever done a transition like this, on this scale, involving so many disparate networks controlled by so many people in so many countries. How do you know that 50% at 3 decades is slow? Maybe this is just the par time for this kind of thing.