> If that’s not a failure I hate to see what is.

How would several billion smartphones be able to connect to the Internet without IPv6?

There isn't enough RFC 1918 (or 100.64.0.0/10) space for IPv4-only to be practical: Comcast—not even mobile—went to IPv6 because running their TR-069 management over multiple 10/8 became untenable.

IPv6 is making all sorts of things possible without most people realizing it.