I think the key term here is "organized crime." The other groups may have a loose organization, but aren't as structured, nor can they infiltrate the "legitimate" world like LCN...the mob has and still does corrupt businesses/govt/police..the others are nowhere near as capable of doing that. Having said that, LCN's influence has waned considerably in accomplishing those things.
2 points:
1: Cocaine cartels are as structured as ANY criminal organisation.
2. Apart from a few fantasists in Chicago the days of LCN (USA) infiltration government/police etc are LONG gone.