Try the following:
$ nslookup github.com
[...]
Non-authoritative answer:
Name: github.com
Address: 140.82.121.3
See also the completely ignored post in their forums.
Same. I’m hearing it’s a must-have for like 15 years now. It still obviously isn’t a real must-have.
This is because ISPs keep piling on workaround after workaround in order to scale their use of IPv4, which is working but not without some disadvantages. Also, like other commenters mentioned, the western world have an unfair advantage in IPv4 addresses allocation and thus people living there don’t really see any meaningful shortage of IPv4. People in other countries don’t have this luxury and have to rely on IPv6 and shitty CGNAT in order to stay online.
I remember hearing that it meant every device could have a unique IP. But we still have NAT…