Introduction The evolution of society is a complex process that depends on numerous factors impacting the emergence and increased importance of particular trends or tendencies. At the same time, the precondition the appearance of specific policies regulating the functioning of institutions or spheres fundamental for the development of communities. However, there are always some groups that promote one or another regulation as it falls within their interests and helps to fulfill their current needs. In fact, the existence of these groups and their struggle for influence are the central moving forces of societies evolution (Lebow 2017). That is why there are numerous theories suggested to investigate these issues. Definition For instance, a self-interest theory is one of the conceptions suggested to explain individuals or groups decisions. It states that all individuals actions always spring from diverse self-interested motivations that appear under the impact of different factors (Lebow 2017). In other words, while acting from self-interest, a person aims at his/her own good or improvement of the current position. The given theory could be applied both to single individuals and their groups as every unit of this sort will act regarding its own interests and try to empower its position by pursuing particular goals (Lebow, 2017). In such a way, the self-interest theory becomes one of the fundamental approaches that could be used to explain the nature of individuals actions. Power of Groups Nevertheless, speaking about specific interest groups mentioned above, their ability to impact the evolution of the society should be explained. The fact is that the political power of these coalitions consists of several factors. First, they should possess a significant capital to impact leading policymakers and certain population groups by donations, advertising campaigns, and sponsorship (“Interest group and elite theories,” n.d.). Second, the given group should be involved in the political life of the state to be able to impact policies and regulations that might be undesired for them (“Interest group and elite theories,” n.d.). Finally, the interests of all group members should coincide to ensure that the given coalition will try to achieve a certain goal and devote all resources to attain success. The combination of all these factors results in the transformation of a coalition into a politically powerful unit. Groups and the Evolution of the U.S. Healthcare The importance of these groups could be evidenced by the role they played in the evolution of the U.S. healthcare sector. This sphere perfectly demonstrates the hyperpluralism of multiple interest groups that tried to pursue their own interests by lobbying and donating diverse political powers in the USA (Giaimo, 2014). Since the first stages of the development of healthcare, they have blocked numerous attempts to enact specific health policies and expand the health coverage to all citizens of the state (Giaimo, 2014). It resulted in the appearance of problems with access to healthcare and unfair distributional patterns that excluded some groups from the health system. Major Interest Groups In such a way, it becomes obvious that there are specific interest groups that have a