I think 1 IP address per human was short sighted. We ran out before the human population doubled. But I think a billion per human was someone liking powers of two, and nothing more. “Ipv5” with 48 bit addressing would have done pretty well. As 6 octets or 4 base 12. For humans you could reserve all values <=512 and >256 and have about 50k times as many addresses while people sort themselves out and still be able to see at a glance that they were ipv5 addresses. 1047.258.300.0/24