In medieval times, storefronts used to avoid words and use pictures to describe what they were selling because the public was so illiterate. That's kind of where we are now with movies because they have to not only be mainstream for US audiences--they have to be able to resonate for international ones as well.
Therefore everything waters itself down to "good guys" and "bad guys", so the dialogue (which is going to be subtitled or dubbed) won't matter and any localized cultural references will be few and far between.
This is how Hollywood today operates.
Paul Thomas Anderson doesn't seem to have noticed. Someone ought to tell him.
Back before home-video and all the other competition for people's attention arrived, movies were a more dominant medium that covered a more complete spectrum of topics.
Hollywood's always been primarily genre-driven. The difference, aside from short term influences like the economic circumstances of the last 4 or so years, has been that marketing departments have been more readily able to identify niche markets. So niche market films are marketed to their respective niches. Other films, mainstream or tent-pole fare, are aggressively marketed everywhere. And sure, they're tailored to satisfy a 'lowest common denominator' audience.
They always have been. Hollywood studios didn't gradually transform from noble, art-for-art's-sake intellectuals to base purveyors of watered-down pabulum. They've
always been purveyors of watered-down pabulum.
There was a period from some time in the late '60s to some time in the early '80s where the culture of the primary market was undergoing rapid changes and it wasn't clear what kind of movies it would best respond to. Some small number of younger people were able to prove with unexpected successes that they knew better than the studios what would and wouldn't succeed. And so you got the much-vaunted time of the Hollywood auteur, many of
the films made by whom are unwatchable today, their other successes notwithstanding.
All that's happened since then is that marketing techniques have improved.
And that includes sci-fi. Compare Prometheus to Alien, for instance. Alien was a rather intimate horror movie compared to the epicness of Prometheus. The difference in tone reflects the different role that movies play in people's entertainment now vs. then.
Alien was a half-formed idea greenlit with a minimal budget solely because of the success of Star Wars, which underwent numerous rewrites by studio executives (Ash being an android is probably the biggest such change).
All too often when examining the past, we commit a form of the Texas Sharpshooter fallacy. It was thus, and so it was
intended to be thus, and there were numerous justifying reasons behind its having been thus. When in fact most often these are primarily accidents of circumstance.
Audiences demand to be bludgeoned by shock and awe. If they want something more cerebral they will watch an HBO drama.
HBO dramas aren't replacing something that movies have stopped giving us. They're an entirely new phenomenon giving us something movies have never been able to. The analogy I like to draw is that of short stories versus a novel.