a few guys wouldn't be able to keep watch over that much territory
Why not? The Outfit has had to "watch over" generally the same amount of territory today with half the crews and a fraction of the membership it once had. And one way it's done it, apparently, is by streamlining it's operations. It's not really into anything and everything the way it used to be. It doesn't have a monolithic stranglehold on all criminal enterprises throughout the city. So it doesn't need the manpower it once did.
the syndicate has never had a "monolithic stranglehold" in crime in Chicago
the feds said al tournabene (consigliere) was in charge of the south suburbs
you love quoting the feds and the feds said the south suburbs have operations
