Is it such a myth, though?
IPv6 still causes troubles in deployment.
For example, Android phones (still!!!) don't support stateful DHCPv6. Moreover, DHCPv6 was designed by idiots and out of many options for DUIDs it doesn't allow the most logical one: a user-specified host name.
PMTU in IPv6 is even _more_ broken than in V4 because extension headers just plain don't work in the wide Internet.