I noticed the other day that IPv6 growth is slowing down, as Google measures it. Its access share used to double every ten or eleven months, now it doubles more slowly, and seems likely to reach 20% only in 2017 instead of this year, and if it goes on as in the recent months, 30% in 2018 instead of in 2017.
At a guess, many of most competent ISPs have done their thing and now we're seeing the more sluggish middle. Or? Comments?
In Belgium we're up to 49.5% of Google traffic over IPv6, which is pretty impressive. All major ISP's have IPv6 enabled in a dual-stack setup right now. This works because almost all of them provide an all-in-one modem/router/access point, all remotely managed, so it's easy to just flick a switch on the ISP end and magically have everything go over IPv6.
What's holding back further progress is mostly people with their own NAT routers/DHCP that's not set up for IPv6, or company networks where the transition isn't planned. That's going to change very, very slowly indeed.
If I remember well at least 2-3 years ago it was complicated to measure IPv6 usage on a high-end router, and that was tied to billing.
Every vendor (Cisco/Juniper/Alcatel/Huawei) had a different way to do it and since B2B billing depended on it IPv6 adoption was not as easy as expected.
Every vendor had a different way to measure how much octets went through an interface on IPv6 using SNMP.
And the standard MIB (management information base) for SNMP only gave you IPv4 traffic.
So, if you wanted to measure the traffic you interchange with a third party on IPv6 you had to be tied to a specific way of doing in (some had private or experimental MIBs for that, in other cases you had to move the data through a tunnel and measure traffic inside the tunnel minus overhead.).
Very easy to make mistakes specially if there is a problem with the traffic late at night and somebody forgets to put you in the loop.
Here in France, there have been leading ISPs (Free ADSL), good citizens (SFR), and laggards that keep on dragging their feet (Orange, Numericable). Things got worse when Numericable bought SFR, halting progress with stupid rules in place that when you get the budget version of a contract you don't get IPv6 because reasons.
Let's not get started on "pro" versions where you just don't get IPv6 at all, ever, and on the phone you can even get them mumbling that it's not even on the table (Completel).
I'm on Free and I had to disable IPv6 because one of their routers was dropping about 60% of the IPv6 packets: GitHub, Google, Bitbucket took several minutes to load.
As soon as I switched to IPv4 everything worked fine.
I suppose that nobody at Free is really monitoring their IPv6 network in the same way they do it for IPv4.
In the UK, only one big(-ish) ISP supports IPv6, and 2 significantly smaller ones. BT claim to be pushing it out next year, but they still have a large number of older consumer-end router/modem devices which can't be updated for it, so it'll take another half a decade for those devices to fail and be replaced. Once BT have pushed it out, many of the companies that depend on them for varying things should be able to build implementations fairly quickly.
BTnet (BT's higher-end leased line etc. services) do support native IPv6 fwiw, but when I spoke to them (this was in Scotland) they said no customers ask for IPv6 to be enabled, and it's not enabled by default. (But if you ask them they'll do it no problem - verified to be true.:) But the situation is different with all that older consumer equipment as you say...
Here in Japan, the largest consumer fiber wholesale network (NTT) "supports" IPv6, but you need a separate, $100 router that talks PPPoEv6 since none of the common consumer routers (including the one they provision you with) seem to support it.
I also haven't been able to get PPPoEv6 working in macOS.
I focussed on your suggestion that it had to cost $100.
If people don't need IPv6, then why bother. My impression is that the content providers don't care about IPv6, so I assume they have plenty of IPv4 space.
Some large consumer ISP are short on IPv4 address, but in that case, they will will make sure their customers get IPv6 capable CPEs.
From this: https://www.google.com/intl/en/ipv6/statistics.html doesn't look like it is slowing down, it's not exponential though, but was it really? It's much easier to double up when number of users is low.
Here at Brazil, I know of no consumer facing ISP that supports IPv6. But we have been busy dismantling a quasi-communist government, so things may change faster in the future (if we are successful in the dismantling).
At a guess, many of most competent ISPs have done their thing and now we're seeing the more sluggish middle. Or? Comments?