Star Wars (the original film and its two sequels) uses this (and similar shortcuts in other aspects, like making the storm troopers wear full body armor to be c

Star Wars (the original film and its two sequels) uses this (and similar shortcuts in other aspects, like making the storm troopers wear full body armor to be completely interchangeable, or putting the main characters in a small insular group with no outside friends or living relatives, or giving the evil empire an unspeakable super weapon, or giving the Jedi characters arbitrary convenient magical powers, or making the robot R2D2 able to do almost anything in the empire’s computer systems) as a way of simplifying and clarifying the story. The universe of Star Wars is not supposed to be a realistic one. It’s a mishmash of previous (terrestrial) movie plots, themes, characters, and scenes lightly painted over with a space setting. The different planets are single places, with settings chosen to fit the needs of the storytelling. Think of them as backdrops in a stage play. As far as the films are concerned anything not on screen might as well not exist, and the rest of the various planets don’t need to be consistent with a realistic broader universe. Trying to paint them all in would waste scarce screen time and confuse the audience. Arguably this is one feature that made the “Star Wars universe” hopeless to adapt to try to tell stories with broader context. If you start trying to flesh out the details, the planets, galactic government, spaceship technology, concept of the Jedi, etc. all start to fall apart, because they were never very carefully designed in the first place, but just hacked together to meet the particular needs of the original story.