In F. Scott Fitzgerald's The Great Gatsby, how is Daisy affected by the failure of the dream?

Daisy Buchanan's life is relatively unaffected by the failure of the American Dream, the belief that any person who lives in America can prosper and even become wealthy through hard work and perseverance.  While it appears for a while that her former and current lover, Jay Gatsby, has achieved this dream, once Tom reveals that his fortune was made illegally, it becomes apparent that Gatsby has not.  Gatsby is a bootlegger, someone who profits from the illegal production, distribution, and sale of alcohol during Prohibition.  One cannot be said to have achieved the American Dream if one has to resort to illegal means in order to prosper; however, it becomes clear that no one else in the text can achieve the American Dream through hard work and perseverance alone (consider George Wilson or anyone living in the valley of ashes, for example).  

Once Daisy's husband reveals how it is that Gatsby has acquired his fortune, Nick says, "Her frightened eyes told that whatever intentions, whatever courage she had had, were definitely gone."  It does not take long for Daisy to decide that maintaining the status quo, remaining with her husband even though she finds him "'disgusting,'" is her better option.  In the end, then, her life is relatively unaffected by the failure of the dream, although, mentally, she seems to have realized its impossibility, and that helped her to choose between Gatsby and her husband.