Thanks for the response. I actually agree -- probably should have written that competition was never more than one of many reasons that someone (anyone) *might have* supported those earlier transitions. That said, if you look back at my original response you'll note that I was actually arguing *against* transition rationales based narrowly on "competition" questions. The alternative that I proposed was transition to preserve the "openness of the internet addressing and routing system," especially to new entrants.

I think that the majority of reasons for supporting the previous transitions (i.e., previous impositions of new technical requirements on incumbent network operators), as well as for supporting IPv6, would fit neatly under this rubric. And while your own description of the past circumstances didn't use those specific terms, I believe that the phenomena of "proliferation of class Cs being allocated" and "class Bs running out" that you referred to were both driven in part by demand from initial allocation seekers, a.k.a. "new entrants" -- i.e., we agree on this point.

Of course, during any given duration the majority of newly allocated/assigned IP addresses are probably going to "incumbents" (subsequent allocation seekers), but that's consistent with patterns of growth in every other industry, i.e., it's basically a demographic of statistical artifact of cumulative growth processes (granted, one that can be influenced by various policies). The important distinction, at least until now, is that the growth/IP addressing demand of incumbents was not incompatible with the continued openness of the addressing and routing system to non-incumbents/new entrants.

And of course, I wouldn't have expected these sorts of arguments to figure prominently in IETF et al. meetings and discussion back in the 1980s-1990s. In the main, we're not a bunch of economists and policy makers by profession -- and even those of us who are generally know better than to phrase our technology and policy advocacy in such alien and unsympathetic terms... most of us anyway.

However, even if "openness of the internet addressing and routing system" was never the most popular/resonant rallying cry for specific technology changes, that doesn't mean that this general idea wasn't an important motivator or an influential part of the unspoken context. And even if that sounds implausible too, it still doesn't mean that the *fact* that such openness was preserved, intentionally or otherwise, didn't play an important role in the success of the system to date. Although the verdict of history is never truly final, to me industry openness looks a lot like a universal correlate (i.e., a necessary if not sufficient cause) behind the durability of industry self-governance. If that turns out to be true, then there could be a lot more at stake in the current transition tussle than just the fate of the IP address registries.