My guess is that in modern times, with big-budget movies in particular, the film-making process is way more streamlined and compartmentalized across different teams than it used to be. I mean, the big spectacle CGI action scenes are often developed by completely different teams working at different companies with little direct involvement from the director, apart from occasional feedback. Whereas, back in the day, you’d have Lucas or Kershner hanging out overseeing the ILM crew constructing the models and setting up VFX shots. There was still a lot of compartmentalization and outsourcing involved in the production process of course, just much less of it than today.
The Prequels: I can’t remember any scenes either like those from the OT. Likely due to the green screen or blue screen CGI backgrounds, and the focus of direction. Unless it had a thousand ships or vehicles whizzing around in the background (“so dense, so very dense”), there wasn’t much going on like in the OT.
Yeah. The world of the Prequels is either mostly empty or a chaotic mess. The corridors of the Kamino cloning laboratory, or the halls of the Jedi Temple… where is everyone? There’s usually just the characters required for the scene and some digital backgrounds. The world feels surreal and abstract, not a real physical place you could actually visit. Then you have the opposite phenomenon where the background is a million ships or robots shooting at each other.