It's not a question of better or worse, it's just going to happen....over a period of years. The fact remains that NAT is there, and it remains a transitional mechanism. Really, NAT is a hack. It's not a security mechanism, it's a way to translate a network from set of IPv4 spavce to another, nothing more, nothing less. Sure, it will probably be around for a while since there is a very large deployment of it, however, there will absolutely come a time when there will be a tipping point. The foundation is very well laid already.
Network Engineers, sysadmins and security professionals will need to know IPv6, in my opinion, anyone supporting users or services that use google for pretty much anything or any modern operating system already should have an IPv6 knowledge base.
What enterprises in north america do is really not that relevant. The world has been implementing v6 for a while. It may take 2, 5, 7, 10 years, but it will happen that dual stack will be the standard.