How Ready Is IPv6 To Succeed IPv4?

New submitter unixisc writes: Over the last 2 years, June 6th had been observed as IPv6 day. The first time, IPv6 connections were turned on by participants just for a day, and last year, it was turned on for good. A year later, how successful is the global transition to IPv6? According to Cisco 6labs, adoption rates vary from 50% in Belgium to 6% in China, with the U.S. coming somewhere in the middle at 37%. A lot of issues around IPv6, such as the absence of NAT, have apparently been resolved (NAPT is now available and recognized by the IETF). So what are the remaining issues holding people up — be it ISPs, businesses, consumers or anybody else? When could we be near a year when we could turn off all IPv4 connectivity worldwide on an IPv6 only day and nobody would notice?