a long time ago, in a galaxy far, far away…」 How does this framing device affect

Though Star Wars appears to be set in a futuristic world where intergalactic travel, sentient robots, and laser battles are the norm, the film famously opens by stating that it takes place 「a long time ago, in a galaxy far, far away…」 How does this framing device affect the story?
As a famous trademark sort element of Star Wars, the opening 「a long time ago, in a galaxy far, far away…」 brings us directly into its world, it narrates the background story of each pieces. George Lucas attempt to tell us the entire chronological history of Star Wars in all the related productions(including the prequel trilogy and animation works), and he began with New Hope, a piece of story in the middle. On the other hand, the following episodes and the prequel trilogy are the extension of the original Star Wars(New Hope). The importance of the opening trademarks are they filled all the plot gaps between each episodes, leaves an open opportunity to make more fictions or films ,and saved a lot time for the audience to understand what was going on before the movie begins, traditionally audience needs to discover what happen from the dialogues inside the movie. And as long as the franchise attracted enough fans (obviously Star Wars had a huge success on this) they can keep producing without a chronological storyline.
Another important function of the opening is it bring the setting of futuristic world (intergalactic travel, sentient robots, and laser battles) far far away from us. If we look into the details in the film, robots, starships, future technology reference, etc. all comes from modern life, and the elements we could find similar to spaghetti western, Japanese Jidaigeki, pulp Sci-Fi magazines. But as we were told in the opening trademark, the story sets in a galaxy far far away from us, and it prevents the audience to relate any of the stuffs from the movie to real life, which could really distract them from the world the movie creates.
Since Star Wars came out, many films have learnt this idea of increase the possibility of making sequels or even trilogies when the script was written in order to increase profits, blockbusters particularly. The story happens in its own fantastical world and usually they spend the opening sequence with a narration to briefly explain what was going on before the protagonist appears, usually an epical incident happened ages ago, or some historical moves that might leave some kind of cause for the evil to revenge. If the film makes enough money, it will be easier to produce the sequels or prequels.