During this time period, it is unlikely that a black man will rise to the rank of a CEO. How does this apply to A Raisin in the Sun?

In A Raisin in the Sun, Walter tells
his son Travis that he wants to one day become the CEO (Chief Executive Officer) of his
own company.  But the play is set in Chicago during the 1950s, and since the Civil
Rights movement has not reached its fruition, the opportunities for black Americans were
limited.  As a result, it is unlikely that Walter would be able to realize his dream. 
However, Walter's desires show that he believes in the idealistic vision of the American
Dream.  Walter believes that if he works hard and takes advantage of the opportunties
that come to him, then he will one day be able to reap the benefits of his effort.  He
also believes that his race should not limit the opportunities that come to him and his
family.