Mans Nilsson wrote:
The essence of an IP address is that it is unique. The larger the network area is that recognizes it as unique, the better it is.
With proper layering, network addresses including IP ones, certainly,
uniquely identify *hosts*.
However, with proper layering, *applications* only require uniqueness
of IP+Port, which is enough for the worldwide IPv4 network.
As a result, NAT won the battle against IPv6.
IPv6 addresses are free but useless.
Masataka Ohta
