system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: How come films and tv shows from the 60s to the early 2000s look so different from films today?

What I'm trying to say here is: why the image looks so unique? I don't know if it's because they were not filmed with digital cameras and they didn't have the great picture qualities we have nowadays, but they definitely feel like they were from the past, like if you're watching Back to the Future you think "this is definitely something that was filmed in the 80s" no matter if you're watching a remastered 4K edition or something, it always looks different. Just to give you a clue, whenever someone tries to make a modern film "look old" they barely resemble the aesthetic (most of the time it looks like if an Instagram filter has being applied).
gpt
35mm film has a very high resolution if properly scanned, but many videos from that time period were scanned to be shown on television so they were scanned at 480p.   Hence they look blurry.
They are rescanning the old films, but some they haven't done yet.

Take a look at the 1080p versions of some of the old TV shows they have rescanned, like Perry Mason, and Andy Griffith, you'll be amazed at the clarity.