How does "Winter Dreams" show the theme of preoccupation of wealth (cars, clothing, houses) in the 1920's?
At fourteen, Dexter admires the wealthy men he caddies for at the country club and aspires to be just like them. He defines success as wealth, which in turn will give you status in society. Once he meets Judy Jones, his one goal in life is to become rich enough to marry her. Judy is symbolic of the shallowness of the 1920s society. Dexter equates his happiness and success in life on money and how much a person makes. He's symbolic of those in the 1920s who saw their happiness tied to wealth.
Dexter also chooses a more prestigious college to attend rather than one that would be more affordable. Again, it was more important for him to say he graduated from a "good" school where rich kids would go than to say he had graduated from one considered less prestigious.
The reality of Dexter's "winter dreams" comes home to hit him hard when he hears Judy has lost her beauty and has married a guy who abuses her. This shatters his dreams of the glitzy and glamourous world he had idealized. When Judy no longer conforms to Dexter's idealized view of her, he loses everything.