The party bosses and the people they got elected used to wield all the power in America. But we've democratized many processes, through initiative and referendum laws, and party primaries and caucuses.
Which raises the question: how's that working out for us? Putting more of the machinery of the politics in the hands of the people produces things like ballot measures legalizing marijuana... but also results like Brexit, in the United Kingdom.
The idea that the problems of democracy are solved by more democracy gets a critique from Yale University political scientists Frances Rosenbluth and Ian Shapiro, in Responsible Parties: Saving Democracy From Itself.