Many old movies that are restored perfectly. Yes it's a lot of film grain but you can also see a lot in the background etc. Also id rather have the film grain.

The movies where shot for cinema on 16mm or so and that is pretty high res.

Oh boy, they weren't fuzzy. Some film outclass the clarity and sharpness of modern OLED, even when it was for B category low budget movies, just that most people watched a 4 week old piece of film in bumfuck middle of nowhere cinema. With a scratched up and badly calibrated focus lens and dirty and deteriorated film over a dirty screen.

Anyways, the biggest problem that physical media solves is not the number of pixels, but the bitrate. Tons of information, specially about color, is lost to streaming compression. Pixel density equation means that the quality of what you see is rarely distinguishable between 1080p, 2k and 4k, depending on how far away you sit from the screen and how big it is. For the typical seating accommodation at home and commercial theaters, you won't notice a significant change within FHD and UHD. However, you can definitely tell the difference between the 10Mbps 4k (down to as little as 2Mbps if your connection sucks) that you get from Netflix¹ and the steady 32Mbps that Blu-ray can give you.

¹: BTW, it doesn't matter how fast your internet connection is, the data transferred can get to you at as high speed as you want, but the bitrate of the video file inside the container that the streaming services give you is usually hard capped rather low anyway.