Even in the countries with the highest adoption, it's only around 50% https://www.google.com/intl/en/ipv6/statistics.html#tab=per-...
Realistically adoption will slow down if nothing changes, everyone willing to put the effort in for zero immediate reward has already done so, and some will allow their support to degrade due to low usage.
At some point I guess ipv4 availability will really start to collapse and adoption will speed up again.
Not sure which will come first to be honest, but better if adoption is relatively high when the shit evebtually hits the fan, to avoid the temptation of insane NAT solutions.
[0] https://www.potaroo.net/presentations/2021-03-02-ipv6-deploy...
Or someone less tech savvy but legally savvy figures out that IPv4s are scarce resources, just like, for example, housing, and finds a way to impose their use through regulation in some contexts and to ban their use in other contexts.
I think this will be more like a linear function. As the IPv4 prices increase, the IPv6 adoption increases until it reaches 100%. I don't think that there will be a collapse.
I'll say one thing about Comcast in the US: they have atrocious customer service, scummy upselling, and that horrid wi-fi network sharing... but they do 2 things that mean I'll forever give them a free-pass:
1. They have CBC channels in the US so I can watch the Olympics without watching NBC's horribly dumbed-down, artificially time-shifted, and condescending feed.
2. They have a rock solid IPv6 network for everyone.