The video I posted showed fully-destructible buildings which topple over and leave debris around persistently. I don’t think there are many indestructible supports in Wreaking Zone - just supports which take much more of a beating before they collapse.
Again, Red Faction Guerrilla is incredibly impressive, especially considering it was on last-generation hardware, but in RFG specifically most debris does fall through the ground and disappear, and overall it’s multiple orders of magnitude less complex than what’s going on in Wreaking Zone.