I don't buy the deception theory at all, that it was used to make it hard to determine the year it was made. Everybody has always known which movies are new this year! Or which movie is from 10 years ago. To me, this falls into the common fallacy of "oh people from back then were so dumb/unobservant..." Like the busted myth that Europeans used spices to mask rotten meat.
It seems nobody knows why it started, but it seems pretty intuitive why it's continued -- it looks fancy and formal and important. You went to the Cinema and you had an Experience and at the end it was capped off with a fancy set of Roman Numerals. It's silly like a hundred other aspects of the movies, but it's kind of lovable.
And I can't help but assume that fanciness derives from years being carved in stone as roman numerals for Important Things. On buildings (date of construction), memorials (for wars and important people), and of course gravestones.
I mean, it also wasn't Star Trek 3, it was Star Trek III. Because fancy.
I can tell you for certain that I use Roman numerals on the copyright dates of the videos I make, because I grew up with Roman numeral copyright dates on the TV programmes I grew up watching - even children's programming had it.
For some reason the one that sticks in my mind is the Blue Peter one with a copyright symbol, the old "three boxes" BBC logo, date in Roman numerals and the little stylised sailing ship logo :-)
Anyway, long story short, I use Roman numerals for copyright dates because fancy like.
Interestingly, that's less of a thing over here. e.g., productions of the public broadcasters in Germany usually end with the date in Arabic numerals. Including Sesame Street.
The BBC didn't have copyright statements at the end of the credits until the early 1970s, and initially they used Arabic numerals, but after a couple of years later (the mid/late 70s) switched to Roman numerals, which they've stuck with since. I think the changeover is around the time end credits and channel logos stopped indicating "Colour".
IIRC in 1999 one of the trailers for the BBC's millennium coverage involved years counting up to MM in Roman numerals, which seemed perhaps to be a nod to their use of them in credits.
It's a film from 1939. The grammar of filmmaking has changed dramatically since then -- direction, acting styles, lighting, staging, everything. Watching something from even the 1960s is super weird and kind of alienating.
Films from very long ago are best understood as historical documents. They tell us a story, sure, same as John Wick 4, but they also tell us about the time period they're from.
This isn't something that's unique to film. Novels, too, get harder to connect with as you move decades past their release. Storytelling changed, and the shared context with the author becomes harder and harder to share.
I strongly suspect you were born at the 80's or 90's...
Not to say that modern cinema is perfect, but somebody born at the 60' or 70's would think the 80-90's style is shallow too. Cinema has been getting quicker since it was created.
(I do think it has moved so far into quick takes that it can't help but go back a little now, but I was born at the 80's, so I'm not sure how reliable is my opinion.)
"The grammar of filmmaking has changed dramatically since then"
Yes, it has. But it's questionable if it's been for the better. A bad film from any era is just bad, but I'd contend that a well made one easily crosses the generations. Mention Casablanca for instance, I can honestly say I've never come across anyone who didn't enjoy it or say it's a bad film.
"Watching something from even the 1960s is super weird and kind of alienating."
One has to wonder what you actually like to watch. You likely didn't like Shakespeare at school because it too is dated.
Pity really, you'll have missed a lot.
_
Edit: I'm curious why you find say '60s films weird and alienating. (There's much to criticize but I've never heard that said before.)
First, don't put words in people's mouths. You'll find that doesn't usually engender reasonable discussion.
Casablanca is a good film, but its pacing, storytelling, acting, and direction are all very dated to a modern viewer.
Acting in good films since the 1970s has tended to be far more naturalistic and less stylized, which makes older work feel fake and cloying. That's not always a dealbreaker, though, as you note. It just puts a gulf between a modern viewer and the work that the work has to do more work (so to speak) to bridge.
There's no point arguing with you as we're miles apart, except to say I find most modern films—and many, many old ones unwatchable (usually for different reasons). I just turn them off.
The reasons are many including those that you've mentioned and others especially the pace and horribly tight editing of most modern films/videos—boys let loose with video editors/switching toys instead of the patience and pace of a Moviola. (Incidentally, I've used both.)
Give us examples of films you like then people will tell you why—and what generation you're from.
Incidentally, it's been touted on multiple occasions that Gone With The Wind has been shown somewhere in the world every day since 1939—an all time record. It's a remarkable success story that's crossed many generations, and its production for the era a remarkable technical achievement.
I first saw it decades ago and I enjoyed it, but a large part of my interest was technical, it being one of the first spectacular color films (it still stands up very well by today's standards).
Yes, this would be my hypothesis too. I see Hollywood epics all the way from D.W. Griffith (and the studios that made them) wanting to broadcast an aura of gravitas. And nothing does that like using pretentious Roman numerals. Of course it's all convention nowadays.
The myth is about the reason for the popularity of spices in midieval Europe.
And yes it's busted, because spices were very expensive -- they were luxury. The people who could afford spices were not people who ever found themselves needing to eat rotten meat. And mixing with rotten meat was the last thing you'd do with something as expensive as a spice.
I would guess it started because you can reuse your work (in an age where you are taking a photo of something physical). It's a lot easier to change V to VI than it is to change 5 to 6.
It seems nobody knows why it started, but it seems pretty intuitive why it's continued -- it looks fancy and formal and important. You went to the Cinema and you had an Experience and at the end it was capped off with a fancy set of Roman Numerals. It's silly like a hundred other aspects of the movies, but it's kind of lovable.
And I can't help but assume that fanciness derives from years being carved in stone as roman numerals for Important Things. On buildings (date of construction), memorials (for wars and important people), and of course gravestones.
I mean, it also wasn't Star Trek 3, it was Star Trek III. Because fancy.