(sorry for the rant)

Having worked in many different capacities in Hollywood over a few decades I will say...

... producers have become even more ego-driven and childish...

... writers have devolved from referencing great works of art to referencing cartoons...

... as audience attention spans have diminished to that of a fly.

Having worked on some films that would be considered "art," I can say that most would not -- could not -- be made in current Hollywood. It's beyond sad.

The Hollywood landscape has become vacuous, numbing non-stop 'splosion thrill rides.

There are still some artists making films and not just pushing product, but they are few and far between and often have to scrape together money from many many sources across the world just to get something shot.

With that said...

... I think 30's and 40's films certainly had more dialogue. But that's because early 20th century cinema was heavily influenced by the stage.

Just have to look at ST Discovery and ST Picard, these series are horrible and their audience is even more horrible.

The movie industry - like most entertainment industries - is way more prolific now than it used to be. So it takes that bit longer to look past the mainstream and the wannabe mainstream. But yeah, there are enough films out there that aren't constantly jabbering.

I think the Seventh Seal had nothing but talking from what I remember.

Clarke wrote a short story (called The Sentinel, back in 1948) on which the later works were based.

Also, film technology and audience expectations have both evolved since the 1960s. Kubrick made a "tonal play", which is why there are long silences punctuated by extremely loud passages (of klaxon sirens, say) which mean I can no longer watch it.
Producers are creating what sells, since the Generation Alpha (i.e., those born after the creation of the YouTwitFace social media empire) have chronically short attention spans, they must be enticed to engage in the narrative. A lot of people prefer to avoid the mandatory climax shootout, for instance, by enjoying British crime thrillers (where the public don't have access to guns) and thus the story must rely on other factors to be resolved, like misdirection and deduction (like the dog that didn't bark).

I have heard the exact opposite criticism to that of the OP.
Exactly. It's the inane "realism" of these cynical super-smart protagonists (typically caught in the evil conspiracy of Big Business™) used by writers trying to appeal to viewers' ego. You might call it Idealistic Realism, with the idealistic part the brave and savvy protagonists, and the realism being the "um", "like", "whatever" interjections.

edit: fixed linkie

I like the long silences.

However, of all the movies that came out since 2000, I have seen less than 10.

I'm probably not the demographic filmmakers are interested in.

I watch broadcast television without sound and with subtitles, and skip advertisements whilst seeking mainly news and current affairs.

The demographic for movies is teenagers, since they are prepared to pay the ludicrous prices for privacy (and own no property) to spend time with friends and to date.

I think audience expectations have changed; I think popular filmmaking styles have changed; and I think people also tend to look at older media in general with rose-tinted glasses - we remember a couple of good movies, but forget (almost) all the terrible ones. There's a reason Mystery Science Theater 3000 has had so many terrible movies to mock. It's a bit silly to make generalizations about "the younger generation" or whatnot based on this factor.

In general, this sort of thing will also vary by genre. Of course action/thriller-type movies will be, well, almost nonstop action - whereas horror movies will almost always have a healthy amount of silence (...well, maybe "healthy" isn't the right word for a horror movie :P ) to build tension and drama. More thought-provoking, "cerebral" films will generally have silent moments in order to leave the audience alone with their thoughts, essentially.

Silence is a tool; some films use it well, while others don't. Sometimes it makes the movie better; sometimes it makes it worse. It's all about trying to make the best movie you can, and using the right tools to do so.

The real difference between old movies and newer ones is not the amount of dialogue, is it's functionality.

Modern movies are constantly explaining the plot and reminding the audience of the what's happening in the dialogue.

The trend to make all movies this way started not more than 15, 20 years ago, I'm sure. If you watch big blockbuster, highly commercial movies from before, like Titanic, Forrest Gump, Jurassic Park, they were not written this way.

I suspect this change was partially caused by the rise in popularity of what I'd call a more infantile kind of action movie (super-heroes, new Star Wars, Fast and Furious, Lord of the Rings, etc.).

I think people do enough yabbering IRL so yeah I like to get straight to the point and HULK SMASH it with a NUKE!