Explain why political machines were so successful in the late 1800s

Political machine, in U.S. politics, a party organization, headed by a single boss or small autocratic group, that commands enough votes to maintain political and administrative control of a city, county, or state.

Political machines are characterized by a disciplined and hierarchical organization, reaching down to neighbourhood and block organizers, that enables the machine to respond to the problems of individual neighbourhoods, or even families, in exchange for loyalty at the polls. The term refers to their ability to elect candidates or enact measures with mechanical efficiency and predictability.

Although the primary goal of a political machine is keeping itself in power rather than providing good government, machines have been responsible for restructuring city governments to centralize authority, improving facilities and services, helping to assimilate immigrant groups, and encouraging the growth of business and industry.