[WorldMaker]

One way to think about the timescale is the rollout time versus the expected usage amount of time. IPv6 was also a bit of a "science fiction project". I remember a lot of the early hype for IPv6 was that it was "IP for the whole solar system" or even sometimes "galactic IP". The architects of IPv6 were clear that they were hoping for something like a 1000 years or more of addresses and usage, even expecting nearly every device on the planet (and maybe the whole solar system) needing an IPv6 address and knowing how fast things like the "Internet of Things" were coming down the horizon.

If it is built to last a 1000 years or more, ~25% of internet traffic by the end of the first 30 years isn't a terrible rollout curve. That's 0.3% of its expected lifetime. (Assuming the 1000 years clock started 30 years ago. It's even believable the 1000 years clock starts closer to 90% rollout of IPv6 than to IPv6 announcements 30 years ago. IPv4 address scarcity wasn't truly felt until decades into IPv4 usage, though it was an academic concern.)

Many Internet projects have always run on different timescales compared to the vastly faster timescales people associate with software and even hardware generations. (In part because these rollouts happen across software and hardware generations.) The IP protocol is so deeply fundamental to that, it is somewhat "civilization defining". It would probably be a lot scarier if an upgrade to something fundamental like IP was an "overnight success". Civilizations are built on the timescales of decades and lifetimes. It should not be a surprise that IPv6 rollout has happened on such timescales. We mostly can only hope that the IPv6 architects were as smart as they hoped they were in preparing for the deep, unknown future of the internet, because they knew they were working on a civilation-timescale tool. (Which is exactly why IPv6 is not just "IPv4 with bigger addresses".)

[JohnFen]

> If it is built to last a 1000 years or more, ~25% of internet traffic by the end of the first 30 years isn't a terrible rollout curve.

I don't think that measuring the rollout curve relative to the expected lifetime of the thing is reasonable (or at least, useful), though. In terms of something like this, measuring it relative to when IPv4 is simply no longer feasible is better. And that time is very, very near.