Going back to the start of this thread, I personally feel it was when people started getting pc in late sixties / early seventies.
There seemed to be a lot of popular psychology of the time advocating that giving kids toy guns promoted gun violence in later life. Youngsters then found themselves sitting with motivational shows instead of growing up to Wagon Train, Bonanza and Rawhide.
By the time they got to adulthood a Western was deemed 'old school and boring', they wanted lots of colour and movement.
Isn't that what a lot of CGI films now provide?
As I said this is just my opinion
As an opinion that is either contrary, or at least sideways, to yours, how about this?
I have always believed (well, "always" since I started having a liking for contemplation...) that a large part of the popularity of the Western genre came out of the fact that many, very many -- if not most -- Americans were once closer to the land than are we today... There was a time when most Americans lived close to the soil, were involved in raising animals, maybe even had horses -- or, if they lived in a city, had memories of living on farms and ranches in their younger days. So much of the Western scenery used to be more familiar to people than it is today.
Add to that the fact that in those same days, there was no TV and -- for much of the relevant time period -- either little or no movies, radio, etc. Yet people who lived too far from towns to easily go there for entertainment, often resorted to books and magazines to put something interesting into their lives. And those sources of entertainment did things that made the country dweller see excitement going on in a world much like his own...
The Western faded out, yes. In part, imho, that was because everyone had seen it...over and over again. People are always looking for something new.
But it's also somewhat true that the Western is still there, metamorphosed. It underwent a...well, forgive me, but I'd call it a "sea change." It shed many of its trappings, but the things that made it exciting still shows up now and again...but it's in modern garb.
Think about many of the exciting movies you've watched in the last couple of decades. Some of them, I suggest, would have been Westerns, sixty years ago...
The Avengers? Think Magnificent Seven...
Captain America: Civil War? Think of any Western you remember with a lone hero who, in standing up for his principles, ran afoul of the powerful...
(You may by now suspect that for me, the Western is as much about a certain kind of character, as about horses, gun, cow-punching...
