Ok, from what I can glean so far, the dark horse that might help explain the mysterious power Joe the Boss had over the Morellos might be the Camorra.
After the Mafia/Camorra war ended in 1917, there was a merger of sorts that brought men like Rocco Valenti (originally a member of Camorra) into the Morello/Terranova group. Joe the Boss was also in the mix starting from some point unclear, though his Sicilian pedegree means Masseria was likely Cosa Nostra from the get-go, whenever that was.
I am suspecting, and I could be wrong, that Joe the Boss could control the Morellos because some of the old Camorra that were adsorbed into the Morello organization supported him. It's hard to imagine a blood related family of black hand terrorists paying monetary tribute to one man and not assassinating him, no matter how rich he was.
Could it be? The root of Joe the Boss Masseria's power was Camorra?
"For us, rubbin'out a Mustache was just like makin' way for a new building, like we was in the construction business."
