@Calibrigreen

The family Luciano took over was still the largest so it was only logical that he would be the top boss. Maranzano was politically more powerful than Luciano, but he was overcome by greed just like his predecessor. By the time Maranzano was killed everyone was tired of fighting and Luciano made the wise decision to share the profits instead of naming himself capo dei capi and demand tribute by the other bosses.

The 'Corleonesi' is the name given to not only the clan from Corleone but also all their allies. Riina was able to take over because he had shaped secret alliances with people who were working for or with Bontate and Inzerillo. Once they were killed the Corleonesi took over these families. Clearly they were militarily superior because it was a one-sided massacre. The international connections of Bontate and Inzerillo simply transfered over to the Corleonesi because there was too much money at stake at the time.

So in the end, military power outweighs political power.