I'm getting a growing feeling that the main opposition to IPv6 are the system admins, who are afraid that introducing it will have one of the possible outcomes: either it will bring them more work (billions and billions of addresses!) which they are not familiar with (impossible to remember the address!), or it will make most of them obsolete as most network setup work will be automated. And they're probably right on both accounts (starting with the first and going to the latter).