To continue the TV analogy, it is important to remember that there were two very different transitions. Cable subscribers did nothing at all and continue to watch analog TVs: the cable companies were able to preserve the analog signal interface in the home even if the rest of the network had abandoned it. It was the rabbit ear antenna-using TV watchers who had to act, buying converters or new TVs, and unfortunately that segment of the population was the less tech savvy of the two.

From an end user point of view, the IPv4 -> IPv6 transition should be much more like the cable experience than the rabbit ear experience. The ISPs already use different technology to deliver the connection to your home (cable, DSL, satellite) than they do inside your home (ethernet, WiFi), so everyone already has a box to convert between these two formats. These boxes already NAT many reserved addresses onto the single external internet address assigned to your connection. If that external address has to switch to IPv6, the ISPs can reprogram the cable/DSL modems to do that without making you give up IPv4 on your home network. After that switch, whatismyip.com will say you’re using an IPv6 address even though your home computer still thinks you’re using IPv4, just as now it says your address is, say, 18.26.4.9 instead of 192.168.1.2. There’s no equivalent of rabbit ears here, no technology without a box in the middle. Even dialup users can be converted by putting the NAT box on the ISP’s side of the phone lines. Most ISPs already charge extra for public, fixed IP addresses that could be used to host a home server accessible from elsewhere. It’s a small step to giving the rest of the customers NAT’ed addresses.

The other half of the story is whether and when the big players at the core of the network will convert their networks. I don’t know what fraction already have, but there’s a strong financial incentive to be prepared to handle IPv6 and have it deployed before the IPv4 pool is empty, so as to avoid rejecting new customers. I trust this incentive to take care of the core network.

So with the edges taken care of by NATs and the core taken care of by not wanting to go out of business, I think ultimately, when it does happen, the IPv6 transition will much more like Y2K: a non-event thanks to advance planning and adequate preparation spurred by strong economic incentives.