How does the institution ultimately prove to be more powerful than the individual?
In the end, McMurphy is defeated. I would say that this is one way the novel concludes the strength of the institutition over the individual. McMurphy defined himself as being against the system, one that he thought was "out of order." His constant desire to advocate for collectivity and solidarity in the face of a divisive and alienating institutional force helps to bring to light the conflict of individual versus social order. In the end, his own efforts are defeated, for he is not able to bring about the vast idea of social change and transformation that he sought. Yet, I think that while McMurphy fails in his attempts to bring about wide ranging change, he is able to bring about the transformation he sought through Chief Bromden's example. In this light, while he might fail, his sacrifice endures, causing a greater sense of hope in affirming the individual's voice against an oppressive institution.
Despite McMurphy's best efforts to get the other patients in his ward to stand up to Nurse Ratched, when Billy does so, Ratched threatens to tell his mother about his behavior. This terrifies him, and he ends up committing suicide. This is the first example of the institution winning over the individual. When McMurphy finds out about Billy's death, he violently attacks Nurse Ratched. Despite the fact that he can leave anytime, he ends up more or less incarcerated and brain damaged after he is given a lobotomy to treat his violent tendencies. McMurphy's individuality, his desire to triumph over tyranny and unfair treatment, which helped turn things around for so many, is ultimately the cause of his demise and imprisonment, and the institution (the mental hospital) is shown to have more power.