They should never have cried wolf
My personal issue with IPv6 is that it seeks to replace instead of co-exist and I believe that this is what makes the whole thing so hard. Because even if you use IPv6 you're still often depending on IPv4.
My ISP for example supports IPv6, I even have a public IPv6 address. Unfortunately the router only provides this on the outside, on the inside only IPv4 is provided. I once tried to set up the DHCPv6 server but to little avail. And that brings me back to my dilemma: all my internal stuff uses IPv4 so the moment I try to connect to the Internet the first thing it does is contacting an IPv4 gateway. So where's the benefit here?
But I really think that they shouldn't have played cry wolf for so many times. Several times did they share doom scenarios about IPv4 running out and the Internet coming to a grinding halt UNLESS we would embrace the savior that is IPv6. The Internet mostly ignored that and the grinding halt never happened. It doesn't matter if engineers worked hard to prevent that from happening, what matters here is public perception: a doom scenario was predicted, and it never happened.
Not once, not twice but at least four times of the past years. And that's a really sure way to lose credibility. Good luck trying to convince upper management that IPv6 is important: "But haven't we heard those stories all the time now? So why should we invest when everything works just fine?".