Think of all of the hours I have to spend researching the following and implementing it:
1. Does all of the intermediate equipment support it
2. Does my IPAM support it
3. How do I even give ipv6 addresses to my ONTs?
4. How do I keep track of all of the address assignments for x months
5. Does my staff even understand how ipv6 works?
6. Does the off hours call center understand it?
7. Build the servers and add them to all of the monitoring, backups, do updates on them
8. What if I do this and the choice for ipv6 dhcp was wrong and in a year I have to redo it all
etc etc
There are no good answers for any of this that I have seen. There are sometimes 5+ options for everything to do with ipv6. How do I even weigh the pros and cons of approaches I have never used before.
Its hundreds of man hours at a minimum for no benefit other than to be ideologically on the correct side of technology. It will continue to work as it is now with absolutely no hours or risk for 10+ years at least.
My upstreams support it, my ONTs support it but there isnt a nice ipv6 dhcp server with logging and a lookup interface that I have found yet. It probably exists but I don't know what it is.
It is one of the more frustrating parts of trying to explain why we don't all just jump to do this.