By the way, “World IPv6 Launch” is so dramatic name for this. For years many big generators of the content like Google and Facebook have ipv6 DNS-name and working through ipv6. But they are only big islands in the ipv4 ocean of the rest Internet.
The most of the hosters and content providers are have not dual stack, what is stopping of changing protocols in the providers enviroment.
The reason is simple. Unless all Internet have not ipv6 addresses (or dual stack), unless you surrounded ocean of the ipv4, you can not provide only ipv6 to the client without NAT64. The carier grade NAT64, that cost like airplane (maybe is not, but you caught my idea). Maybe you have money for this (maybe not) but in any case, you will not be able to earn money on this. It is expenditure item.
Until IPv6 is not profitable, the big boys have only choise – are declaring “IPv6 day”, making promotion of the new protocol and pushing the resting world to the future in baby steps.
And give new features to the CG NAT, like new private network, that has been declared recently.