Most Earth cities grow from small settlements in locations that benefited humanity either in the convenience of trade routes or the abundance of natural resources, preferably both. What was, in the eighth century, a tiny town of farmers and trappers, might grow to be a thriving metropolis by the sixteenth century.
Few cities are planned from the ground up. It’s simply not practical. Just like a bunch of teenagers, humans say to each other “I’m not moving there unless all my friends are moving there too” and there are numerous examples of planned cities that remained empty or had to be repurposed and rezoned.
Loonies do not have the luxury of plopping themselves down wherever they feel like it and planting a city. Whereas an Earthling can find a random plot of land and eke out a living for themselves and their family, doing so on the moon is wildly impractical and prohibitively expensive. Only a handful of people have ever succeeded, and that was only accomplished with vast wealth and incredible luck.
A century ago, the disparate cities of Luna banded together and formed a united government, albeit a rather loose one. Before then, the individual cities were planned and built by different governments, corporations, and, in at least one case, a group of people who improbably said to each other ‘Hey! Let’s go to the moon!’ and somehow made it work. I use the term ‘disparate’ because it was very difficult to compare one city to another. Some were simply corporate offices and housing, where the employees owed their souls to the company store. (I’m being dramatic. It wasn’t like that. Usually.) Some were idyllic utopias that quickly became dystopian as soon as their population reached a certain level. Many were kept small by design, with strict rules about who could get in. Others were designed for growth, and quickly became vast metropolises.
All had their own systems of governing, or the lack thereof.
Today, it is more difficult to tell the difference between one city and another when one is standing on a random street-corner. Luna has developed a flavor all its own. When viewed from orbit or from some other distant vantage point, most of the larger cities have a certain look to them. Mordor is fortress-like and has their iconic Tolkeinesque tower. Memphis is a pyramid. The Cube is…well…a cube. The North Pole is particularly fanciful. But although every city or township on the moon governs itself, you can’t commit a crime in one then go hide in another. There are some local currencies, but Lunar dollars are accepted everywhere. There’s a broad mix of languages everywhere you go, and most people freely add words from at least six different tongues into their everyday speech.