I don't understand why they didn't just add two or four more fields to ipv4 e.g. 0.91.127.0.0.1 is localhost where 0.91 can be omitted in the local context.
PS: I don't understand how networking works. Feels very very complex and full of jargons.
It's a fact of life that working with networking that we'll have to work with IP addresses at some level. It's easy to tell someone, "hey try typing in 'ping 8.8.8.8' and tell me what you get".
The readability of IPv6 is, in my opinion, worse with repeated symbols and more characters to remember. The symbols that were chosen were also poorly thought out. Colons are used in networking a lot of times when you want to connect to a service on a particular port, so if you want to visit 2001:4860:4860::8888 in your browser, you have to enclose the address in square brackets.
The wackiest example I've seen of this is the `ipv6-literal.net` notation for Windows UNC paths: https://devblogs.microsoft.com/oldnewthing/20100915-00/?p=12...
Because they thought that 64-bits would not be enough, and did not want to have to go through yet another transition.
The IPng proposal that was chosen, SIPP, was originally 'only' 64-bits:
* https://datatracker.ietf.org/doc/html/rfc1752#section-9
See also §10.2:
* https://datatracker.ietf.org/doc/html/rfc1752#section-10.2
Specifically (§11.1):
* scale - an address size of 128 bits easily meets the need to
address 10**9 networks even in the face of the inherent
inefficiency of address allocation for efficient routing