I guess it’s supposed to represent America. Daisy has old money, she’s the remaining aspect of English aristocracy that still held influence over America at the time, and Jay represented the rising meritocracy. Gatsby is an average Joe turned soldier turned millionaire, and it’s still not enough for Daisy to choose him. Gatsby, like America, was chasing after something they would never get; the glory of the jazz age was waning, and Gatsby endured all the superficial partying to retain the appearance that society wanted from him, yet the green light was always just out of his reach.