[FullyFunctional]

That comment is incredibly uninsightful. In reality, the majority of the Internet is still not on IPv6 meaning that you still can't make do (easily) with only an IPv6 connection. Dan's point are true regardless of the adoption rate.

[oasisbob]

Sure you can - many of us have phones in our pockets right now which are doing just that over LTE.

With an imaginary phone running with an imaginary v4 extended address, you'd still need something in the network at the carrier side to handle communications with legacy devices.

There's not much difference between that and having a v6-only device.