Olson Olson's groundbreaking work, the thrust of which is almost intuitive to modern students of politics and social movements, explores the nature and dynamics of collective action the essence of political activity. He laid the foundation for a voluminous literature addressing the barriers to effective collective mobilization. Before Olson, almost all social scientists assumed that people would instinctively or naturally act on common interests, and that inaction needed to be explained. Popular conceptions of the import of Olson's work abound.
Group size is a key factor.
You'll note that above that Olson makes an exception for small groups. In this respect his analysis is Simmelian. He actually alludes to Simmel and his emphasis on the influence of group size on the nature of interaction. But there are other considerations. He has a broader array of interest that he is attempting to realize through his activities.