Gatsby's vision is based on the belief that the past can be repeated and that sufficient wealth can allow him to control his own fate. When Gatsby is told that no one can repeat the past, he responds, "Can't repeat the past? Why of course you can! (p.116)" His failure to see that youth and Daisy's love are behind him shows the inevitability of his vision's failure. Furthermore, Gatsby believes he can win his woman with riches and Daisy can only achieve his ideal through material influence. He establishes an immense fortune to impress his great love, Daisy, who is only in love with his material success. Gatsby's downfall is brought upon him by his own inability to realize he cannot buy a perfect love or life.
Gatsby is a very capable man but he fails to see the inevitable downfall of his ideal world. Up until his death he never realizes the actual world and his "universe of ineffable gaudiness (p.105)" cannot coexist.