I would love to see a more recent source if you have one.

Regardless, possession of IP addresses doesn’t change all that much. In the early days a company could buy an entire Class A (1.X.X.X) address space comprising 16million+ addresses for their private use. There are still many companies holding large blocks of addresses, and most of those companies are in the US, and they don’t just give up those addresses.

The point being, there’s significant resistance to redistributing addresses once they’ve been allocated. They don’t change hands terribly often (and keep in mind we’re talking about actual internet addresses, not local network addresses that are being dynamically assigned and NATed across router domains).