Any failure experienced is largely a failure of management/accounts to invest in the future for something that the media can not turn into sound bites and flashy images. This displays a clear lack of enlightened self interest.
Even in my home office, over the last nine years I have observed continually increasing IPv6 access for myself and my clients. Comcast has demonstrated that IPv6 has no deleterious effect on typical user experience. Apple and Microsoft have provided admirable support for IPv6 coexisting with IPv4 on end systems. I suggest that it may be more important to deploy solutions to BufferBloat, to the benefit of both IPv4 and IPv6 since it will improve the user experience, than to try to extend IPv4 lifetime, an effort with diminishing returns.