We had low latency input and smooth animation 30 years ago. The latency and lag of modern user interfaces is all in the layers and layers of software. It's especially noticeable when you look at like NES games and the like, they ran at 50 or 60 FPS (depending on PAL or NTSC) and typically had zero input lag (unless there was some sprite limit being exceeded). Modern games at 50 FPS are so sluggish you feel like you've downed a full bottle of wine or something. The difference is the time it takes to render a frame today, which can be 100ms or more, especially when the GPU is struggling.

But what I meant was like pixel density and so on. My screen is a lot higher resolution than it was 20 years ago, but it doesn't actually display much more information as my ability to actually resolve fine details has if anything worsened with the years. My screen is farther away and my font size higher, that's the big difference.