Ironically, their excuses make sense in context. Not all people will find technical superiority as a good argument(Linux vs Windows), as any doubt or excuse wil

Ironically, their excuses make sense in context. Not all people will find technical superiority as a good argument(Linux vs Windows), as any doubt or excuse will be judged as another benefit of maintaining the status quo. The cost of switching is a real thing, they don't feel the Ipv4 exhaustion pressure personally and the old thing works. And there are some unfortunate details in IPv6 deployment decisions that make switching harder or costly enough, just enough to use alternatives fixes(like NAT) or maintain some cludge to route IPv6 without actually supporting it(read https://en.wikipedia.org/wiki/6to4 https://en.wikipedia.org/wiki/6to4 ).