This is only true if you can get IPv6 connectivity to all your important locations. This turns out to be not so easy even in 2016. E.g. Charter Cable has no IPv6. AWS has no IPv6.
HE.net's free tunnel broker is pretty awesome. They'll even speak BGP to you for free if you have your own allocation, which is no longer that expensive.
Furthermore, simply using IPv6 internally - and you can route it over the internet via VPNs etc - is a huge win.
E.g. you can give each docker container a globally routable address. Globally might be 'within your network', or perhaps you have translators from global IP space to your own internally routable space at the edge of the network.
Don't you have all this with v4? Sure, but not as easily. With v6 you can route subnets and re-route sub-subnets. And you can do this all day long without running out of address space. Doing that in v4 is much harder.
AWS has supported IPv6 on the edge for several years. What they haven't supported is IPv6 internally. I sometimes wonder if it's because they are running a home-built IP stack on custom gear, and just haven't bothered to adding IPv6 yet.
The neither the newer VPC ELBs nor CloudFront support IPv6. Not even the Route53 DNS servers have an IPv6 address. With very few exceptions, there is no IPv6 support on AWS, internal or external.
Furthermore, simply using IPv6 internally - and you can route it over the internet via VPNs etc - is a huge win.
E.g. you can give each docker container a globally routable address. Globally might be 'within your network', or perhaps you have translators from global IP space to your own internally routable space at the edge of the network.
Don't you have all this with v4? Sure, but not as easily. With v6 you can route subnets and re-route sub-subnets. And you can do this all day long without running out of address space. Doing that in v4 is much harder.