Good idea for a thread!
For myself, I've wondered whether the growing women's movement in the period had anything to do with Alma coming to feel that she deserved a better life than she was having and finally getting up the gumption to dump Ennis.
On the other hand, despite all the changes that went on in the world during those years, we don't really know how aware Ennis is of them (I suspect Jack would have been more aware). Yes, he had television, even in that poky little trailer he's living in at the end of the film. But even today, in the metropolitan Northeastern U.S., I know people--coworkers--who are tremendously unaware of what is going on in the larger world around them--they never watch television news (because it's "too depressing"), they never read newspapers, and so forth.
Personally, I tend to think the sight of David Bowie in a dress and makeup would have horrified Ennis, made him even more rigid than he was to begin with--if he felt that David Bowie in a dress and makeup equated to being gay.