Why does the party end with a car crash involving the owl-eyed man?

The party ends with a car crash involving the owl-eyed man as a symbolic representation of the chaos and recklessness surrounding Gatsby's extravagant lifestyle. The owl-eyed man, who is fascinated by Gatsby's lavish parties, becomes a victim of the excess and moral decay that permeates the world of the elite in the novel. This incident underscores the consequences of indulgence and the fragility of the American Dream, highlighting how the pursuit of wealth can lead to destruction. Ultimately, the crash serves as a stark reminder of the underlying emptiness in the characters' lives.