I always compared Sunset Valley to an old, well-established beach town like Monterey or Carmel-by-the-Sea in California. The structures and houses there are decades/centuries old, especially closer to the ocean, and most of the usable space has long been occupied, so you don't see a whole lot of new designs except where old buildings were renovated or torn down and replaced. The areas where you do see more modern houses (like Thornton Wolff and his neighbors' houses with the enormous windows and decks facing the ocean) tend to be on the edges of town where expansion happened over time.
Anyway, those towns don't look out of place in 2020 but also wouldn't look out of place in the mid-1900s. The buildings have just lasted a long time, as buildings often do (although less so in California lately). I imagine Sunset Valley to be like those towns.
