That counter is when global registries have allocated everything, not strictly when all useable addresses are in use. IPv4 addresses will never "run out", they

That counter is when global registries have allocated everything, not strictly when all useable addresses are in use. IPv4 addresses will never "run out", they will just get more expensive and complicated to use until the point where IPv6 is cheaper and easier. IANA exhaustion is just one big milestone along that path.