AWS still has no native IPv6 support. It's sad really. It's pointless for a project like LE to make IPv6 a first-priority feature when massive providers running the backbone of the internet don't support IPv6 without a ton of fiddling-around.
I have IPv6 at home now but still don't have it at our tech-oriented co-working space, and I've never seen an IPv6 address get handed out at a coffee shop, airport, restaurant, etc.
My ISP doesn't support IPv6, but I've just checked and a Windows 10 machine was able to do `curl -6 https://ipv6.google.com/` just fine.
And I think I've heard OS X has something as well... not sure, don't have OS X or iOS devices at hand to try it out.
(On GNU/Linux and BSD machines there's a lot of choices, Miredo, 6to4, AICCU from SixXS - whatever one fancies. As usual on *nix systems, setup is manual, though.)
That's like focusing on supporting Internet Explorer 8. At some point IPv4 will become the legacy protocol and supporting it will be annoying and expensive.
That day maybe not be today, but switching protocols is not always trivial, and you should start yesterday.
AWS's services are great but many people just need compute. I don't understand why people who just need compute use AWS, since for compute only Digital Ocean and Vultr destroy it in virtually every way: ease of use, performance, cost, IPv6, etc.
Digital Ocean now has block storage too, which plugs one hole. Of course they don't have things like RedShift or S3, but like I said not everyone needs that.