There was something in the Sixth Family, some sort of arrest or something that really clipped Grecos wings, and gave the Cotronis the upper hand in Montreal.

That combined with Bonnano being forced out, Galante and Ormento and all those guys who controlled all the distribution being locked up, AND the heroin trade from Sicily being disrupted by that car bomb meant for Salvatore Greco. AND all the Sicilian Mafiosi having to disperse and go into hiding, the Sicilian component was thoroughly in disarray, save for a few like Badalamenti, Buscetta, the Grecos.....WHO BECAME GAMBINO ALLIES DURING THIS TIME PERIOD -late sixties early to mid seventies.

The independent family idea most likely had to take a back seat until the drug routes were figured out....