The ignorance here is frustrating, would be nice if people could read up on the topic.
Yes, any dual stack implementation prioritize IPv6 over IPv4 - that is how it is supposed to work - a host does DNS lookup and if AAAA record exists, that will be used first, and if connection fails it will try the A record. OSX for a long time chose any record it received first from the lookup, but they have fixed that. Smaller devices should not have the overload of full dual-stack, so DS-lite (yeah, ha ha) was developed, that helps them reach IPv4 hosts even though they are primarly IPv6 only.
Any device that is dual stack is also ready to be IPv6 only, and since IPv4 address space is nothing short if being used up, and the IPv4 routing tables get bigger and bigger due to the fragmentation, IPv6 more and more emerges as the cheap and easy way out - when that happens it is bye-bye IPv4 for most ISPs.
NAT wont help you squat, there is NAT64 that today helps people to run IPv6 only LANs to reach IPv4 services, which many wireless providers already do, especially ar universities where thousands and thousand of devices are hooked up at once. Other likely IPv6 devices are cable TV boxes, I know ComCast at least are working a lot with IPv6 in their TV boxes.
My major point is this - the day your ISP says "%&$#?@!%&$#?@!%&$#?@!%&$#?@!it, enough of this IPv4 legacy crap", you are screwed, ISPs can easily flip over night and vast majority of users will not notice. You see, this is how the teansition is meant to work! And no, they will not develop a special magic router just for us retro fans.
