Why did movie stars in old Hollywood movies appear more beautiful?
I think your suppositions 1 and 3 answer your question. Stars were heavily groomed in the “Golden Age” of Hollywood. It was a system: wardrobe, hair, diction, etc. But there was also just a different type of storytelling and filmmaking then. It’s not just that B/W photography was used (though not nearly exclusively) but that B/W requires more attention to lighting for better depth/contrast, and to promote the star system, glamour lighting and techniques were used: women stars were generally in softer/more diffused light (less direct) but also lit brighter than their co-stars, and the focus tended to be softer. (Sharp focus is not as forgiving; and in contrast, men would appear more rugged/masculine.) Filmmaking now (and for the last 40-50 years or so) tends to aspire more toward verisimilitude (less glamour, fantasy). There was also more media control over what you saw of stars. You almost never saw (non-staged) ungroomed, dressed-down photos of them, and that helped perpetuate the mys
