I do wonder if as beauty standards change the beautiful people of earlier era look more normal to future viewers, because they don't fit our beauty standards? Perhaps people in the 1920s looked at The Freshman and thought everyone looked unnaturally gorgeous then, too.

But I do think it's at least partly a real phenomenon, not just a change in perception, though. If you look at, say, action sequences in 1960s TV, the actors are fit, but they aren't dehydrated within an inch of their lives to make their abs stand out like in a modern-day superhero movie.