Bright like pastel (but also messy)

Hm - why is it that nearly every modern game, which wants to call oneself "realistic" at the same time, still looks like one bright motley pixel mashup? Even those presenting themselves with a background scenario that is downright inviting for a darker overall layout seem to do that... (And Overwatch only is like the peak of the iceberg which introduced this visual design. It exists for far longer already.)
Even Dos-Games all didn't try so hard to be like a comic.