Tl;dr this night time image is 95% TWO COLORS. The dark gray is illustrated as pink and green.
This is me, holding a shotgun, pointing at a dead scav in the streets fountain at night. I could not see anything, so I thought it was a monitor issue. I took a screenshot and checked it out in Photoshop. Turns out, this image was almost only TWO single colors! I colored them in with the paint bucket (0 tolerance, no anti-aliasing) to better illustrate my point.
Back when I was into DVD's, one major quirk was poorly mastered movies with what was called "crushed black levels". Basically, the color pallette was compressed. This turned many nuances near each other into the same color, losing a lot of detail. What would be a moody dark scene became black mud.
What causes this? Your guess is as good as mine. It is not a engine limitation of Unity. My take is that BSG uses this to create artifical void darkness out of artistic choice, either ignoring or being unaware of the issues it causes. Perhaps it's more taxing on staff or hardware to do it correctly.
There are many other ways to darken scenes. This ain't it, chief.
