There is no licensing for internet providers and that's a good thing. Most ISPs in the US already provide IPv6. 45% of users access Google over IPv6 and this has been increasing linearly for the last decade: https://www.google.com/intl/en/ipv6/statistics.html
The final barrier is crappy consumer routers with terrible default settings. Not much we can do but wait for these devices to die because the average user won't buy a new one until that happens
> Most ISPs in the US already provide IPv6. 45% of users...
Is that distorted by cellular providers?
I know my wired ISP does not provide IPv6, even when I explicitly asked for it. They do CGNAT for most customers and assign a static IPv4 to anyone who complains (and then try to start charging for it a year later).
The ISP at my previous home was also IPv4 only (although, thankfully, no CGNAT).
Probably a bit, though I have noticed an upward trend in v6 support with ISPs.
When I was using Spectrum, was pleased to find they had (barely-passable) support, SLAAC wasn't a thing IIRC. Google Fiber has done well and so did AT&T's offering
Ok, fair enough. If Spectrum and AT&T both support v6 now (edit: Comcast/Xfinity too!), then that probably does cover a good portion of the wired ISP market.
Last I checked, most of that IPv6 traffic was mobile, and most residential ISPs don't offer IPv6, or if they do in areas, they don't always provide IPv6-ready equipment. We're in a similar situation up here in Canada - adoption is slowly trickling in through mobile networks, but many large ISPs still aren't offering it.
The final barrier is crappy consumer routers with terrible default settings. Not much we can do but wait for these devices to die because the average user won't buy a new one until that happens