This is just vibes on my part but I feel like a part of that modern emptiness is not having enough extras onscreen. In Dune there were these huge sets shot in a way that highlighted the emptiness, maybe they thought having fewer people in them made them feel more epic? maybe it's just cheaper. The Atreides are heads of a planet-spanning aristocracy which has no "thinking machines". Surely they'd have attendants everywhere! Fremen sietches, and Arakkeen, should be absolutely bustling.

Blade Runner 2049 is a more open question. The design of LA suggests a huge population density but Earth's ecology is so fucked that surely we have population decline, so many of those apartments should be empty.