<chuckle> Yes, indeed - although there was a fairly large contingent that felt IPng would just suddenly take off at depletion of the IPv4 free pool if vendors pushed it, and that it?s success was assured even if IPng had no benefit over IPv4 with regard to feature parity (IPv6 AH/EH vis-a-vis IPv4 IPsec, etc.)
The reality was that such sudden & rapid deployment occuring at IPv4 runout was unlikely even if we delivered a working protocol with "a straightforward transition plan from the current IPv4? ? and it was even more remote without a clear, in-hand working transition strategy. When combined the near inevitable arrival of IPv4 NAT, it made for a particularly poor prognosis for IPng (when compared to IPv4 & NAT.)
In 1994, during the IPng process, I penned a warning in this regard <
https://www.rfc-editor.org/rfc/rfc1669.txt <
https://www.rfc-editor.org/rfc/rfc1669.txt>> -
No internetworking vendor (whether host, router, or service vendor)
can afford to deploy and support products and services which are not
desired in the marketplace. Given the potential proliferation of
network address translation devices, it is not clear that IPng will
secure sufficient following to attain market viability. In the past,
we have seen internetworking protocols fail in the marketplace
despite vendor deployment and IPng cannot succeed if it is not
deployed by organizations. As currently envisioned, IPng may not be
ambitious enough in the delivery of new capabilities to compete
against IPv4 and the inevitable arrival of network address
translation devices. In order to meet the requirement for "viability
in the marketplace', IPng needs to deliver clearly improved
functionality over IPv4 while offering some form transparent access
between the IPv4 and IPng communities once IPv4 address depletion has
occurred.
About two decades later, at the time of the IPv4 central free pool runout (Feb 2011), we had neither ?clearly improved functionality? nor a straightforward transition plan for "transparent access between the IPv4 and IPng communities? ? I do hope I was wrong about the outlook for IPng under such conditions, but we?ll need to wait for another few decades to know for sure one way or the other.
Best wishes,
/John