I agree with Steve Roby's points. Personally, I never remember giving a thought to how old a movie was or whether it was in black & white. But, when I was a kid (also born in 1969) there were lots of old movies on TV, where we now have infomercials, daytime talk or "judge" shows, and there wasn't much else to watch. So older film was just part of the background, and I didn't notice till I was a lot older the big differences in acting and directing style. It was just how old movies were, you understood that and it never crossed your mind that it would be otherwise..
So I'm trying to imagine the perspective of kids raised on almost completely contemporary or recent entertainment. I have to admit that the old kind of stage-trained, presentational acting, combined with the style of dialogue writing, does sound pretty unnatural, if not bizarre. Old soundstage sets can look pretty phony. Black and white, well, it's not how we really see the world. I guess the viewer might benefit from some kind of background primer, sort of "these were the limitations of the time, and this is what they did to deal with them, and these became the standards, and this is why they did that." But, sometimes people just want to watch something and be entertained, and not have to have any specialized knowledge, and I can see how a person would give up on a movie that is presented in, to them, a very foreign format.
I also think that pictures of the US code period can seem quaint or naive because of their mild language, soft-pedaled sex and attenuated violence. But don't believe it! The ways directors addressed more adult themes sideways in old movies is often very impressive. Take "Shane," for example, which is usually regarded as a harmless, classic Western, which my class watched in elementary school. But it has a brutal, almost sociopathic killer, gives the bad guy a nice speech where he raises some points about his position that test the viewer's thinking, and there's a whole other thing going on between Shane and Joey's mom.
I think if someone watches enough good old movies they will become accustomed to the older style and won't think about it anymore.
As for Metropolis, I again agree with Steve Roby. I don't think you have to like it, but when something is as widely influential and highly regarded, it has some pretty solid merits going for it. Everything came from something, and having a familiarity with something pioneering like that can give you a better appreciation of stuff you like that came later.
As for literature, written English hasn't changed enough in 200 years for me to even worry about it.
--Justin