I'm not sure which of you I'm replying to. The comment was made on NANOG the other day that we should discount Google statistics because they have been promoting IPv6 for a decade. It's true that they have been doing so. But they aren't the only people with statistics.
You might look at the following links. Eric Vyncke has been putting up charts basically on Google, Akamai, and APNIC statistics for a while. One thing to consider is that around 90 countries (92 in this capture, as low as 89 a couple of days ago) have 5% or greater response rate using IPv6. Google and Akamai have their own content networks, and in at least some countries only externalize AAAA records or respond to IPv6 requests. APNI isn't that way; they don't operate a content network, but rather accept traffic from across the backbone. Consider that a content network essentially reports traffic from a customer network to their first hop ISP, while when APNIC reports an IPv6 access, the father form APNIC to the collector in question has to include every network and every router in the path. Now look at these:
I think the APNIC numbers demonstrate that paths through the backbone generally support IPv6 end to end, and that from a routing perspective there is no reason to favor IPv4.
There are 8 Countries (this evening) that Google reports roughly equal response rates from using IPv4 or IPv6. cf https://www.vyncke.org/ipv6status/compare.php?metric=p&countries=in,my,sa,be,de,fr,gr,vn. This doesn't prove that IPv6 has taken over the world, but it does prove that those who would discount available statistics sources are a little too shrill in doing so.
Where IPv6 has a problem today is with enterprise. IMHO, this is basically because enterprise is looking at the bottom line. If ISPs were to do what Mythic Beasts says they do, which is charge their users for address space, IPv6 is virtually free while IPv4 costs something. I suspect that enterprise would change its tune dramatically.