There’s lots of random stuff going on in the world, they just don’t make a big deal out of it so you usually walk right past it.There are actually two places I've seen in the game that spawn gang wars. One is near the north east of the city where Militech is sieging a Dynalar building with robots and guards are fighting back. That's a great pick up place for gear btw because the event respawns if you pass enough in-game time away from the location.
Another is somewhere in the project burbs of the 6th Street Gang where they are shooting at others (Valentino's?). They couldn't be damaged though so it's probably some unfinished shyt.
I've also encountered random car robberies out in the Badlands. So there are definitely unmarked events in the game but they are very rare and feel like leftover content.