I know what you mean. It’s annoying when a bit of continuity error or historical framing gets in the way of a good story. But then that’s is part of my pedantic nature. So irritating! It would be good to watch a film and not notice things like that!

My favorites are "3:10 to Yuma" (both versions) and the newer version of True Grit.

There's a trope that says "Most writers are writers". They don't know what historical times were like, but they sure know how to take the plot of a '30s gangster movie and set it in the Wild West! (Or whatever the explanation for that particular plot point.)

One of my favorites has always been "The Good, the Bad, & the Ugly", in which Sergio Leone gets history wrong (like most Westerns) by having it set in the Civil War, but featuring quite a few guns from the 1870s and 80s. Also, dynamite wasn't invented until 1867. And as for parting a hanging rope with a bullet...

But it's all worth it for hearing Eli Wallach's parting line at Eastwood as it turns into the closing theme song: "HEY BLONDIE! YOU KNOW WHAT YOU ARE?! JUST A DIRTY SON OF A" aa-AA-aa-AA-ahhhh

I used to know a Lebanese guy, who told me he grew up watching American Westerns, with Arabic sub-titles. (Somehow, I can't imagine what Matt Dillon, or Festus would sound like in Arabic). He also said that when he came to America as a child, he expected it to be like in the Western movies and tv shows.The Western genre also became very popular in West Germany during the Cold War. In Stalin's Russia, episodes of the Three Stooges were shown in movie theaters, to illustrate what Americans were like. It is interesting how the cultural trappings we export, help to form foreigner's opinions of us. It is also scary, considering you can now watch The Simpsons, South Park, and American Dad in almost any country on the planet. We can only wonder what Extraterrestrials must think of us!

Jeans were invented in 1873. That's the same year that Colts Firearms Company introduced the peacemaker (single action army) revolver, the Springfield Rifle was adopted by the US Army, and Winchester improved its famous lever action rifle significantly. The jeans featured a tiny pocket inside the right front pocket that was designed to hold a pocket watch.

The classic adventure tale and in many parts, the standard "Western" format was created by James Fennimore Cooper - a man who never got farther West than upstate New York. His novels and series The Leatherstocking Tales began the Western mythos of frontiersmen and Native Americans. Since then, the myth of the cowboy arose building off what Cooper created.
To your question - people with little to no knowledge of the West write or wrote about it. (Sidenote: during the "depression" of 1872 thousands went West - keeping that time from being declared a depression - and in that group thousands of blacks as well, who were later pushed out, burned out, and whole communities destroyed. I've wondered the "what if" two marginalised groups had united).