Melinda Shore wrote: The problems we're seeing from NATs - and they're considerable
It depends of the situation; don't generalize, the reality of numbers is against you. The number of sites where NAT works just fine is orders of magnitude greater than the number of sites where it causes more than minor inconveniences.
How can you say "the number of sites where NAT works just fine"?
Have you operated such sites with and without NAT and compared the result by asking all the users?
Or, does it just mean that network operators they operate their network just fine?
We're the IETF; we don't design the Internet for the select few that have issues with NAT, we design it for everyone.
Design what? IP network beyond NAT is not part of the Internet.
I have the greatest respect to Economics Nobel prize winners but I have never met one that has half of a clue on what it takes to operate an enterprise network on a daily basis. There is a difference between "the market" and "what the market would/could be if this or that". How many of these Nobel prizes understand the relationship between NAT and renumbering (opposed to the obvious and moot "save IP addresses" and "security" ones)?
The only thing economists should observe is that ISP service with a lot of IP addresses is charged a lot more than that with a single IP address.
The difference reflects the real world evaluation on the cost of NAT.
Masataka Ohta