[decadence]

It is a reflection I feel of advancement of society and even technology.

There was a time when Westerns were very popular. Perhaps because the American perception of 'hero' has changed, this is no longer as true. The idea of cowboys against [the other race of] indians is now more anathaemic to contemporary societal values.

Time was when a lady could not bare herself onscreen, only her soul. These days it is practically wall to wall nipples. Once though, suggestion was all that people could get away with. Take the film Double Indemnity for example (1940s film noir with Barbara Stanwyck at the femme fatale). There was plenty of suggestion, but she was in a long flowing dress with an anklet to hint at a more declassé side. These days, if they wanted a star to convey sex appeal they'd just include plenty of flesh. With an obligatory sex scene or two on the side. When more was covered up, there had to be more suggestion and a more "ladylike" appearance. The Hayes Code (restriction on movies in that era) would never have allowed films to be passed which would "corrupt" society.

Also, technology has moved things on. The 1920s (?) film Jazz Singer was one of the first 'talkies'. Before then films were silent. A lot of actresses and actors couldn't find work when that change happened; as their voices didn't fit roles.
Similarly in earlier times a big scar across the face meant you'd play a bad guy only. With makeup, special effects etc that net has widened.

Take the films of director Douglas Sirk, e.g. Written on the Wind or all that Heaven Allows (1950s). They would be films of small town life perhaps where the 'lady' "knew her place" and being on the straight and narrow was good. As a director in the days of the studio system he could only use subtlety to convey it was a fallacy, that under a veneer good and bad weren't quite so separate. Contemporary director David Lynch much more openly portrays the idea of the respectable small town, the lady and the gentleman being a fallacy; in films like Blue Velvet. Perhaps, only the tweed worn over the bad boys/girls has been removed.

Perhaps the gentleman, too is a dying breed and films reflect that. The more warped views of feminism (viz. less equality more supremacy) have pushed aside the image of the well spoken gent opening doors, or walking on the outside of the road so the lady does not get splashed by a horseless carriage. I'm not saying manners have gone but the image of an upper class, refined person has faded. Perhaps more actors like this are seen from Britain as they might be more believable in this image; it's probably only an image for them. I've seen men in bowler hats maybe once or twice in my life. : - )

There are onscreen personas. Gone are the days when we couldn't tell the difference and would expect onscreen doctors to diagnose us! However, stars are expected to carefully cultivate an offscreen image too. The Olsen sisters are expected to be clean to occupy their niche and sit well with parents and kids. Other stars are expected to appeal to their market with the presumption sex sells. Sometimes publicists may even engineer 'relationships' for them to push their image of the vivacious young star.
In earlier cinematic days of the studio system it was about illusion. Stars were contracted to a studio for a period and could only make films for them. The studio could impose huge restrictions on stars, they were in a position of power. The studios could also suppress harmful media stories back then. Firstly because the public didn't want to hear it (there was a story or two about some top stars back in the day that wasn't accepted), and secondly as they could refuse access to all their stars for interviews etc or prescreenings if that media outlet harmed one star.