You can't just assume linear growth. Your link acknowledges this, and the "prediction" you refer to has the right caveat: "we can look at the time series shown in Figure 1 and ask the question: 'If the growth trend of IPv6 adoption continues at its current rate, how long will it take for every device to be IPv6 capable?'". It's using such a naïve model to illustrate that we're still nowhere close to completing the transition, not to say that we'll be done in 20 years at most as you suggest.
Adoption will slow down and my guess is that we'll be stuck with a long tail forever, and only time will tell if that happens at 50% adoption or 90% adoption.
> Adoption will slow down and my guess is that we'll be stuck with a long tail forever, and only time will tell if that happens at 50% adoption or 90% adoption.
But that long tail will probably look like figure 4 of that link, only reversed: IPv4 running mostly as tunnels over a core IPv6 network. Some large cellphone networks are already at that stage, using things like 464XLAT to run IPv4 with NAT over an IPv6 network.
I'm not talking about a long tail of systems and networks which still have working IPv4 support. I'm talking about a long tail of systems and networks which still don't have working IPv6 support.
I would agree with you were it not for the fact that I'm personally investing my time into a FLOSS project to make sure the growth does not slow down by making “tomorrow NOT like today”, but gets a kick in the butt once we reach the 50% deployment inflection point instead. Stay tuned ;-)
Whatever you're cooking up, I wish you luck! My life would be significantly easier if I could just completely ignore one network protocol, be that v4 or v6. So far I have mostly just ignored v6 and everything I do uses v4, but I have no strong preference (except that v4 addresses fit in my brain while v6 addresses do not, which is honestly a not-insignificant reason why v6 is hard)
Here's to hoping, but I agree one way or another one stack needs to go :-)
BTW: Contact info is in my profile if anyone wants the inside scoop. The project just isn't fully ready for public launch yet, but we're well into the cooking.
Adoption will slow down and my guess is that we'll be stuck with a long tail forever, and only time will tell if that happens at 50% adoption or 90% adoption.