Oh man 1 i can actually answer for once!!
So basically back in the 30s and 40s the Film Industry had a full monopoly and control over the whole visual entertainment, Since Television was not out till 1949. It was pretty normal for people to go out and see 5 to 7 movies a week at the time, so the Industry being a business first they found out that people liked certain genres more than others, this being Western, Musical, and Noir. Which such high demand for these films, the Industry would pump out hundreds of films a year for each genre.
Now this did have draw backs at the time, since the Film Industry wanted to maximize profits, they didn’t allow for director and writers to branch out and try new things in the business. Their ideals were make ” safe non offensive movies that everyone can recognize and want to see”, and since they controlled all aspects of the industry, the actors, writers, studios, directors, and even the cinema’s and promotion were all employed by the industry majors.
This business model basically killed off film as an art form and a form of expression for a few years, until Television hit the scene in the early 50s, suddenly cinemas lost a lot of profits fast, and with the nature of competition in a business, The film Industry had to now adapt since now their average 5 – 7 views per persons a week is no longer a thing. They let go of their tight grip on director, actors, and writers, anything to get people back on those seats. More R rated films came out and other genres like Sci-fy blew up. At the same time they started trying out gimmick like 3D glasses. Basically you can thank Television for saving film as an art form.
EDIT: The information I got for this post was given to me by my online college Library. This video has all the information I stated above in full detail and more. Not sure if it is Log in gated to non students. But here is the direct link to their site seems to be a pay wall
A) Westerns were extremely cheap to film B) Some of the cowboys were still alive or only recently died when the genre hit its peak, adding a hint of romantic nostalgia.
C) The increased availability to foreign markets helped as well, along with people fascinated by america’s wild west.
You may have heard the term “spaghetti western”. They were called this because of the amount of italian companies financing them. Cheap and profitable with a global audience. It’s partly why foreigners often think all americans have a “cowboy” attitude.
It’s cheap and easy to film movies like Westerns. Modern films spend lots of money on locations, special effects, and props. In a Western you don’t need most of that. The hills of Southern California are west-looking and easy to get to. (Eventually they’d move to Italy and Spain because it was cheaper due to various factors.) All the special effects you need are some blanks and some little explosives called squibs to replicate bullet hits. The props are simple: a few wagons, some horses, and guns.
Somebody finally mentioned silents! Yes, class, there were movies before the 30s and 40s–they were also a thing in the 20s and teens and the aughts! In fact, they were quite a going concern pretty much right at their start in the 1890’s. So, first of all, almost nothing outofnames11 said has any factual basis–your college library needs to up its game, bro (if bro you be). That comment was pretty fact-lite, sad to say.
The first films (in the US) were made in studios on the east coast, only later did they move out west to Hollywood, with Cecil B. DeMille and Lasky Studio, 1913. Not that their first film there, The Squaw Man, 1914, was the first Western genre film ever made; it wasn’t. That was 1903’s The Great Train Robbery, filmed in the Edison studios in New York City with location shooting in New Jersey. Many subsequent silents were made in these places.
There are probably many existential reasons why the Western has proven to be such a long-lasting and popular genre. At its start, however, as has been cited in other comments, it was all about the action. Silent pictures relied on action rather than speech, and during their time Westerns were a perfect fit for that. Another reason, and not the least of which, was because there were plenty of actual cowboys around to be in them. If one had been tripping over magicians in LA at the time, perhaps our film mythology would all be about top-hatted bunny-pullers, instead.
Finally, I think it could be argued that without John Ford (director from silents forward) the Western would not have had the durability that the genre had. It would certainly lack most if not all of its most iconic offerings.
A lot of what I’ll say is speculation but let’s start with the fact that Edison gets credit for making Hollywood the movie capital of America. Edison pretty much owned the movie business because he owned the patents for the technology so people who didn’t want to deal with Edison went to the other side of the country.
It’s impossible to know for sure but if the movie industry had stayed centered on the East Coast maybe you get more city dramas.
Now consider films began silent. Even though there are productions such as Shakespeare plays, anything that really relies on dialogue is at a disadvantage.
Even today people love watching good guys and bad guys shooting guns at each other. Westerns make this easy, along with the other popular early genre of gangster films.
Obviously there were no World War II movies before World War II. The American involvement in World War I was relatively minor and besides to do that subject takes a lot more than horses and a Western town studio lot.
On the other hand you had things like dime novels https://en.wikipedia.org/wiki/Dime_novel and Buffalo Bill’s show https://en.wikipedia.org/wiki/Buffalo_Bill telling stories about the Wild West. You have Oklahoma, New Mexico, and Arizona becoming states 1907 to 1912. With the majority of the US population o nthe East Coast, the Western becomes stories about another world far away.
Finally, we get to simple star power like Tex Allen https://en.wikipedia.org/wiki/Robert_Allen_(actor) and Roy Rogers https://en.wikipedia.org/wiki/Roy_Rogers and their horses. People were happy to watch them do the same thing again and again. They didn’t want to put them in suits or police uniforms or to pretend to be anything other than cowboy heroes.
It’s easy to do a process of elimination where it was too early for some genres such as sci-fi, costs were an issue for other genres like the big musical productions, technology was not ready even for things like the early cheesy monster movies, and so on.
Add on top of that our distorted view backwards. Many early films have been lost. Many early films are in archives and no one really cares to bother since outside of historical interest there is little entertainment to modern sensibilities. I don’t know if anyone has done percentages but I wouldn’t be surprised to learn if Westerns were a smaller percentage of what was made but more of what we still care about from that era.
The Western is almost unique as a genre because it was a time and place concurrent with the start of movies but the Wild West no longer exists. Comedies, dramas, action, crime, horror, war, etc. evolve and move on but not the Western. We might finally be at a point where the genre has essentially reached its end where new Westerns are rare and quickly forgotten but it will always be iconic to the history and culture of the United States.