What is resource mobilization theory? how do social movements develop according to this theory?

Resource Mobilization Theory states that for

''any social movement to move forward, you need a core team of professionals activists who manage all the resources of the organization such as fundraising, media viability, organization management, lobbying etc in order to move towards the common goal of the movement''

According to the theory, people are rational beings who have certain problems and grievances with the system. Only by weighing in the costs and benefits of a particular movement do people support a cause and work for it. 

Also, every social movement is goal-oriented and there is a certain mission that everyone tries to achieve.

A well developed and administrated mobilization of resources will achieve maximum impact.