Well, one saying is that "there is no way to stop the power of an idea whose time has come". I have noticed the same, and I can give you my personal opinion on the answer to your question.
One point is that IPv6 is inevitable, as there is no other answer/solution to the address issue. Above this, IPv6 offers many advantages over IPv4. So the clever mind says, "Why should I invest in expanding my IPv4 infrastructure, if I can invest in the future protocol, IPv6?"
In Asia, IPv6 has been alive quite some time, but the wave has also started in Europe and in the U.S. For instance, the Department of Defense (DoD) announced in 2003 that they will migrate their network to IPv6 by 2008 -- and that from now on, they will only buy hardware and software that supports IPv6.
Guess what vendors do? If they want a piece of the DoD IT budget cake, they have to support it. Google has recently been assigned a /32 prefix, so -- who knows? -- maybe we can google over IPv6 in the near future.
IPv6 is a wave approaching, and just like with other technologies, today we can't imagine running our networks over IPv6; tomorrow we may wonder how we did it without IPv6.
Other drivers that I can think of would be mobility demands and VoIP, as well as needs for end-to-end security, which requires plenty of addresses and no NAT.
For more information, learn about the move to IPv6 in this Migration to IPv6 video interview with John Curran.
This was first published in May 2005