I'm on a small rural ISP which uses carrier grade NAT and it's working very well. Yes, it's a nuisance to not be able to use IPv6 without a tunnel, but I shudder to think about all the work this ISP would have to do to add IPv6 for their users. The two employees are already working to capacity so they would have to hire extra manpower to do that as well as deal with all their clients having problems stemming from a changeover, and I really don't think there is an economic incentive to do so.
Perhaps it's time for government grants for small providers. I just don't see us reaching the point where IPv6 becomes an absolute necessity for a very long time. It's going to take a lot more than the insistent begging and nagging from the IETF.