I'd assume a lot of this is because of mobile devices of some type. Getting legacy network operators like cable providers to supply IPv6 has been hell.
> Getting legacy network operators like cable providers to supply IPv6 has been hell.
In my experience it's actually the large enterprises that are having issues.
Eyeball networks and cloud providers have been implementing IPv6. In the US all major phone carriers are v6 only with XLAT, the large residential ISP all have implemented v6 (Charter/Spectrum, Comcast/Xfinity, altice/optimum). The lagging networks are smaller residential ISP and enterprise networks.
In Asia they've implemented v6 everywhere pretty much because their v4 allocation is woefully insufficient. APNIC has like 4 billion people in it but less IP space than ARIN, with a population of less than 500 million.