Why does crooks reject the dream of a ranch after curley's wife leaves his room?

Curley's Wife represents the failure to achieve dreams in OMAM, so arguably once she's left Crooks' room he realises that he is destined to be treated in the way he is at the moment. As a result, he dismisses working on George & Lennie's farm as mere fantasy.

This is just as well, as following the death of C'sW the dream of farm ownership never transpires so it could be seen as a metaphor for the domed nature of the dream about the farm