Following Kieren's link, one can find Google's stats of IPv6 users, which tells a whole different story than the doom'n'gloom he's peddling, with a rather steady growth:
"the utterly idiotic decision by the IETF 20 years ago not to make IPv6 backwards compatible with IPv4. We still haven’t seen or read a good explanation for what that decision was made"
Isn't that akin to demanding an explanation of why motorcars were not made backward compatible with horses? That seems like something that could explain the lack of an answer.