It is great to see NANOG members describing some of the real barriers to widespread IPv6 deployment. Buggy implementations, lack of consumer demand, too many other things to do (like rapidly deploying fiber to customers before they switch to a competitor), lack of IPv6 expertise at ISPs, lack of ISP demand driving lack of supplier support, and doubled testing and qualification workload. As Tim Howe <tim.h@bendtel.com> wrote:
... I do not really blame those who don't, because in order to get where we are I had to make it my personal mission in life to get to a passive FTTP configuration that would work with functional parity between v4 and v6... For over a year I had to test gear, which requires a lot of time and effort and study and support and managerial latitude. I had to isolate bugs and spend the time reporting them, which often means making a pain in the butt out of yourself and championing the issue with the vendor (sometimes it means committing to buying things). I had to INSIST on support from vendors and refuse to buy things that didn't work. I had to buy new gear I would not have otherwise needed. I also had to "fire" a couple of vendors and purge them from my network; I even sent back an entire shipment of gear to a vendor due to broken promises. Basically I had to be extremely unreasonable. My position is unique in that I was able to do these things and get away with it. I can't blame anyone for not going down that road.
What struck me is how NONE of those challenges in doing IPv6 deployment in the field had anything to do with fending off attempts to make IPv4 better. Let me say that again. Among all the reasons why IPv6 didn't take over the world, NONE of them is "because we spent all our time improving IPv4 standards instead". John Gilmore