If you want to look over the Western genre’s entire history, it does seem like it was most popular some decades ago, rather than a few years. Many of the essential ones, like High Noon, The Searchers, and The Good, the Bad and the Ugly, came out around the middle of the 20th century or a bit after. But then, a little later on, you did have Best Picture winners like Dances with Wolves and Unforgiven (both from the early 1990s).
