I've been looking into keeping my network IPv4 in an IPv6 world, and it looks like there are a lot of sharp corners and kinks that make that problematic.
In any case, considerations like that are part of why I'm putting off any serious effort or decisions until it's required.
The reason it's problematic is the same reason we need a new protocol in the first place: because the old one isn't enough.
You've spent longer talking about not deploying v6 than you would have done deploying it. I said this before, but I suggest you sit down and turn v6 on for your network -- and *just* that, don't start gaming out how to disable v4 or deal with devices that don't support v6 or anything else, *just* do the basic enabling v6 on the network part. That way you'll see that you're seriously overthinking it.
> You've spent longer talking about not deploying v6 than you would have done deploying it.
I guarantee that I haven't.
> I suggest you sit down and turn v6 on for your network
I did this a long while ago. I apologize for giving the impression that I haven't. But actually using IPv6 in any serious way takes more than just turning it on. It requires reconfiguring a nontrivial number of machines/devices, figuring out how to accommodate the many machines/devices that aren't able to use IPv6, and so forth.
Now, I will admit that I'm still learning IPv6 stuff and as a result there are likely things that I'm overthinking. But responses like yours don't move that ball forward any. You're just scolding people for not being experts.
In any case, considerations like that are part of why I'm putting off any serious effort or decisions until it's required.