I think they only appear slow because they don’t have the frenetic fast cut style of modern movies. They linger on shots longer, they have characters talking over one another in a realistic way, rather than one after the other for easy consumption. 2001 and Star Trek definitely like to linger over their special effects a lot. I think Close Encounters and Alien are just wonderfully plotted films that function as mysteries first. The audience doesn’t know what’s happening at times, same as the characters, and the movie’s not in a rush to let them in on the secret.
I don't think you can say they only
appear to be slow. The fact that they linger on shots longer and don't have the fast cut of modern films is what makes them slow. Interestingly, of all the ones I named,
Alien is the shortest, clocking in at just under 2 hours. The rest are all between 2 and 2.5 hours long.
Also, if you think about
2001: A Space Odyssey, during its 2+ hour runtime, there are less than 40 minutes of dialogue. And a lot of that dialogue is spoken slowly and calmly (like with HAL and his hypnotic voice).
Speaking of HAL and his hypnotic voice ... that's what makes me wonder if these films were meant to be watched while high. I mean, it was the 70s after all, right? But like, I watched the director's cut of
Apocalypse Now once, and I definitely felt like I would have enjoyed it more if I'd been high.
Kids in my extended family all begged to watch the prequels instead of Star Wars because "it's soooo sloooow" by 21st century standards. Their Generation X elders were mortified until we realized how far we were into the movie and everyone's still dicking around on Tattooine.
Interesting. I don't think any of my Gen Z / alpha children have ever complained about the first Star Wars feeling slow, and they like pretty much all the Star Wars films. I
will admit that if you watch
Rogue One then
A New Hope back-to-back, then the latter does feel a bit slow in comparison, but still not
as slow as those other 70s sci-fi films.
I don't think I could ever sit through
Close Encounters again (having only watched it as a teen), and I'm an elder millennial with Gen X siblings.
And the Pink Panther was a zippy, zany film by 1970s standards -- which makes it about normal paced today.
I think you could argue that the first one is slow, but the rest of them are pretty zippy.
A slow sci-fi / fantasy movie by modern standards would be the first Hobbit movie. Man, that thing drags, especially in the first half.