> The current problem with IPv6 adoption is that nobody has yet said "let's stop processing IPv4 traffic"

Mobile carriers have done that between consumer devices and network towers. That forced a lot of innovation (including tools like better DNS64 and "happy eyeballs" protocols) and network stack hardening.

The roll out of out CGNAT in some cases is "let's drop IPv4 traffic randomly" and "happy eyeballs" in consumer devices is transparently driving a lot of consumer traffic to IPv6.

This is why mobile and consumer devices are leading the pack on IPv6 adoption.

It's maybe not all of Google that next needs to say "we're going to stop accepting IPv4 traffic", it's maybe more specifically GCP (and AWS and Azure) that need to do that to drive the non-consumer IPv6 push we need. The next best thing would be for all the cloud providers to at least start raising IPv4 address prices until their clients start to feel them.