And there's no real reason to do it either given the availability of global IPv6 addresses and any of the free tunnel brokers/teredo/etc, other than the simple

And there's no real reason to do it either given the availability of global IPv6 addresses and any of the free tunnel brokers/teredo/etc, other than the simple lack of adoption/momentum. Most ISPs will need a push, but from an infrastructure perspective it just boils down to a new gateway router or a firmware upgrade. It doesn't even need replacing the end-user equipment if ISPs simply set up a tunnel server for their own customers as a transitional measure.