Since my post, THQ Nordic announced they're re-releasing Red Faction Guerrilla, and the Red Faction series was discontinued for poor sales... we can hope!
I think DF was actually one of the bigger franchises they acquired from a sales perspective... According to Wikipedia's entry on DFLW, "Combined sales of all Delta Force computer games released between January 2000 and August 2006 had reached 1.7 million units in the United States by the latter date." (
Source)