Bobby Trosclair, in the comments, says in a few paragraphs what I said in twelve pages:
I have to agree that Lucas stumbled upon a conservative plot probably by accident in the first film. One has only to look at his first SF film, THX-1138, to see a film that was steeped in the doom-and-gloom views of much of 1960s and 1970s dystopian fiction.But, having written that, I have to question that premise – was the poor critical and box-office reaction to THX-1138 what led Lucas to appropriate wholesale the pop-culture motifs from an earlier, saner time? Did he recognize the cinematic dead-end such tales led to?
(And as anyone who grew up in that era recognizes, THX-1138 was just one in a long line of dark, dystopian, and apocalyptic SF films of that era – SOYLENT GREEN, ZPG, ROLLERBALL, PHASE IV, LOGAN’S RUN, WESTWORLD, FUTUREWORLD, COLOSSUS: THE FORBIN PROJECT, A CLOCKWORK ORANGE, PUNISHMENT PARK, A BOY AND HIS DOG, DEATH RACE 2000… I have personal affection for a lot of those films, but all of them and THX-1138 shared the same dark Manichean world-view: the world is a crappy place, The Man will crush your free spirit, and individual heroism will earn at best only a temporary victory. It was the cinematic equivalent of a lot of the trends going on in the New Wave movement of SF literature.)
Lucas evoked the older tropes of a more Christian, even chivalric worldview (although I doubt he would recognize it as such) – where a community of like-minded, noble individuals can overcome the soul-deadening power of dark forces by doing what is right. It changed the nature of cinematic SF (in some ways for the better, arguably in some ways for the worse by creating a horde of imitators that copied the form but lacked the substance. I am not familiar enough with Lucas’s statements to say whether this was a conscious and commercial attempt to offer a bright, lively, and engaging alternative to the dystopian alternatives of the era.
And it’s of interest that many of the tropes that Lucas, cough, “borrowed” were from earlier eras, or from alternative genre worldviews of Lucas’s own approximate era that did not share the same Manichean world view – the Tolkienish (and very Catholic) fellowship of disparate heroes, assisted by a noble, sword-wielding wizard (played by the very Catholic Alec Guinness, perhaps coincidentally) who falls in battle and rises again to assist the fellowship; the scene-for-scene shots of aerial battles from WWII films like THE DAM BUSTERS; Jack Kirby’s Old Testament-derived comic book visions of the Fourth World, with a mystical “Source” that binds and unites all things and which can be manipulated by hero and villain alike (not to mention Kirby and Lee’s creation of a certain scarred, armored and cloaked Dr. Doom, master of both scientific and mystical powers); Japanese samurai films; western revenge dramas like NEVADA SMITH, the hero of which returns from the desert to find his family killed and burnt by marauders and who must be mentored by an older warrior-figure to pursue his quest; the upbeat, can-do Flash Gordon and Buck Rogers serials and shows; Frank Herbert’s Dune series, with its desert planet, sand worms, oppressive galactic empires led by an evil emperor and clans that control mystical powers and are able to control weak-minded enemies by the power of the voice alone and princesses Leia and Aliyah; even 1950s era comic books like “Planet Stories,” in which the alien villains (the Voltamen) of a long-running series (“Lost World”, written by SF pro Jerome Bixby) spoke with the exact same idiosyncratic speech patterns as Yoda, essentially Latin translated word for word into English, verb at the end and so forth: “Me to your leader take”; the planet-size weapons and psionic powers and Jedi-like galactic protective corps in E.E. Smith’s Lensmen series. And so forth.
In all these sources, heroism is not simply an alternative but the only alternative both individually and as part of a group, and the universe is not seen as inherently evil, but as an often wondrous place which is a stage for human creativity and nobility.