The encroachment of "civilization" on the west, and the contradiction between the kind of behavior required to "tame" it and the kind deemed acceptable in a community is the theme of just about every Ford Western, from the silents though Stagecoach, Clementine and the Cavalry films through the twins The Searchers and Two Rode Together, and the elegiac Liberty Valance and Cheyenne Autumn. It's so dominant in Ford's Westerns that it's sometimes conflated with the genre as a whole.
By the 60s, most of the great Western directors had either moved on or been shoved aside. Not so much from changes in the genre or audience as the collapse of the studio system and the ravages of age. Hawks and Ford still made a couple great ones in the 60s, but Mann and Fuller and Boetticher and Ray were doing other things, if they found work at all.