> Hell, going from 199.120.121.122 to 199.120.121.122.123 will have expanded IPv4 by 254 times. It took us, what? 40 years to exhaust Ipv4... Just increasing it by 254 alone is insane large amount.

In it's original design, SIPP, the design that was chosen for IPng had 'only' 64-bits, but it was decided that it would be impossible do another transition, and going to 128 would be better future-proofing:

* https://datatracker.ietf.org/doc/html/rfc1752#section-9

So 199.120.121.122 could have grown to 199.120.121.122.152.183.166.197, which I do not think would have made a practical difference to those who complain about "hard to remember" addresses.

And it took 40 years to exhaust IPv4 because NAT was invented (RFC 1631), and now we're stuck with that kludge and have to have all sorts of workaround for it (ICE/TURN/STUN). IMHO it has also has contributed to the centralization of the Internet because doing P2P is just a pain in the ass.