writes "The mistake in the design of IPv6 is not really in the technology. The mistake does not lie in the design of the protocol itself, but in the incompatibility of the addresses. Because it is not a technological but a administrative problem, there will hardly be a technical solution for it.
The future is hard to predict and it will be hard to predict how long IPv4 will live, but one thing is sure: What ever will come after it, it won't be IPv6."Link to Original Source