I have no v4 on this machine. I'd disable the v4 stack on it if that was a thing Linux could do, but as it stands it's just sitting there doing nothing.

The thing you're claiming is not going to happen is something I'm already doing.

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 protocol supersedes one or both.

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.

It won't be just a couple. That's the point.

The curve is at 50% after an astonishingly long time and is already flattening.