Three years ago all groups were supposed to have converted completely to IPv6 by the end of the year. Never happened.
Back then the exhaustion of IPv4 addresses was "any day now". I guess someone must have found a closet with a bunch more of them somewhere.
I think for us operations types IPv6 is still too complicated. I mean when someone says "hey, what's the IP of that web server?", saying "192.168.13.129" is easy. You can even memorize an address like that. "fe80::2bdd:d4c5:f093:300a", not so much.
Besides the IPv4 address exhaustion problem I don't think anyone has made a compelling argument for IPv6 yet. At least not on the ground.