Earlier quoted context omitted.
I was talking about internet at large. You , and many clients, are of course able to do it on your box, but to use the whole internet, you will at some point hit a translation point which uses v4. The point is the internet at large is never going to reach a point where there won't be two internets; at this point it is pretty clear v6-only will not be a thing with the current set of technologies before a future protoc…
There were always expected to be v4 hosts on the Internet effectively indefinitely. That's not a failure condition for v6. "There are a couple of v4-only hosts out there somewhere" would be kind of irrelevant if most ISPs stop bothering to provide v4 service.
The curve is at 50% after an astonishingly long time and is already flattening.