To answer this question we need to understand that Elisa is a character who is fundamentally trapped and restricted in a world where she is unable to fulfill her own dreams and potential. The description of the Salinas valley at the very beginning of the story immediately creates this sensation for us. Eliza, although she is presented as a strong character who has survived life in this claustraphobic farm, nevertheless feels she wants and needs more. At the end of the story, having understood that the sense of connection she felt with the tinker was actually false, she feels the urge and need for more than her life currently gives her and this is what is expressed through her request for wine and to go and see the prize fights.
However, although this seems to indicate that Eliza's character is strong enough to break out of the confines of her life and forge ahead, fashioning a new kind of life and identity for herself, it becomes very quickly clear to both Elisa and to us as readers that actually, she is not strong enough to do this. Her breakdown at the end of the story shows that asking for wine at dinner is the extent of her ability to try and change her fate:
"It will be enough if we can have wine. It will be plenty." She turned up her coat collar so he could not see that she was crying weakly--like an old woman.
The abiding image we leave the story with is of course Elisa, described as an "old woman" who is weak and broken by her inability to escape her life and its confines. Asking for wine is the extent of her strength to try and fashion freedom for herself.