Who benefited from bossism?

Bossism refers to having a political party that is run by a strong leader, the "party boss," who along with his associates, determines everything from which candidates can get elected to which policies will get attention. In American history, there are been times when both parties have succumbed to Bossism, and in certain cities, the "political machine" of one candidate was so powerful that it became nearly impossible for challengers to even have a chance, no matter how good their ideas might have been. It is usually a politician who is already in power (a mayor, a governor) and wants to stay there who benefits from bossism, since he (and it is usually a male) is often the one who sets up the mechanisms to make sure he stays in control.