| I guess there's a large pool of IP addresses used by residential ISPs that could be recycled relatively easily. When I lived in Ireland I only got a public IPv6, my IPv4 was behind CG-NAT. The nerd in me wasn't a fan of that on paper, but in reality I didn't have any issues with it. I could see ISPs making a quick buck by switching to CG-NAT on IPv4 so they can sell off their IPv4 blocks. Those IPs being recycled for servers/services doesn't seem too risky, given that they're not typically hosting anything. |
Where an IPv4 solution for your clients only needs change-logging on IPbinding-to-client level, the CG-NAT requires you as an ISP to log every outgoing IPv4/port combination with timestamp to client mapping.
Which requires A LOT more storage and much more expensive equipment.
Going rate per IPv4 is up to $40 nowadays, selling of your v4 block might not be cost-efficient.