> At what point will we be allowed to say IPv6 hasn't failed?

"IPv6 ... still hasn't taken over the world [after thirty years of deployment]." is a very different statement than "IPv6 has failed.".

Noone who has successfully extracted their head from their ass says that IPv6 has failed. It's widely deployed on the Internet, and on who knows how many corporate intranets and SOHO/home LANs.

IMO, it's stupid to ever consider turning off IPv4. There surely exist useful systems out there that will never be updated to work with IPv6.

I see IPv6 as an "IPv4 address pressure relief system". In the future, SOHO/home LANs can run servers on IPv6, datacenters can run servers mostly on IPv6 but also v4 if they really want, and SOHO/home networks can be behind an IPv4 CGN because all of their unsolicited inbound traffic will come over IPv6.

>IPv6 ... still hasn't taken over the world [after thirty years of deployment]." is a very different statement than "IPv6 has failed.".

It's incredibly likely that the GP was referring to comments in this thread, which were indeed claiming that IPv6 has failed, despite the fact that its deployment has been steadily climbing up worldwide.

By the way...

>In the future, SOHO/home LANs can run servers on IPv6

The future is now. My web server is IPv6 only precisely due to the same reason you mentioned: my ISP has put me under a CGNAT. People can still connect to my website through the Cloudflare reverse proxy though (which I have only enabled for IPv4, IPv6 users get to enjoy direct connection).