The thing about IPv6 is it has significant switching costs but almost no benefit to end users. The exception, I guess, is network providers who are struggling with a shortage of v4 addresses.

We've been trying to get people to switch since the late 90s/early 00s. And it's only now making progress because IPv4 address have an actual cost which keeps increasing.

But I think IPv6 is huge example of second system syndrome. Instead of just solving the obvious and most important problem of IP address exhaustion, we piled on a whole bunch of other requirements, greatly expanding the scope, increasing switching cost, and dragging out the migration for literal decades. Here we are 20+ years later with only 40% adoption of IPv6...

And I can see the temptation to bundle in all those other changes, since this might be the big opportunity to get them out there. But seems like we could have come up with a simpler and easier to switch to alternative that would have solved the acute issue much faster.

Instead we're here muddling through.