Lucchese was a powerful mafia figure long before Gambino was even on the radar. He was underboss when Gambino's feet were still wet. Tommy Gambino's marriage to Lucchese's daughter gave a piece of the garment district and JFK to the Gambinos. It previously belong to the Luccheses.
I am of the opinion that Carlo was chosen to be of greater importance than Tommy Lucchese because of his pedigree. Tommy wasn't a relative of the Heroin smuggling families of Sicily. Carlo was. I believe Carlo's pedigree played a part into why he was installed as Boss after the hit against Anastasia.
So Carlo was mafia royalty, Tommy originally was not, in my humble opinion. By intermarrying with Carlo's family, Tommy became mafia royalty.
