I think that the vision of the world shown in Hamid's work is one in which the fear of terrorism has altered diplomatic and personal relations. It is terrorism that has become a reality infiltrating much in the world. The nostalgia that Changez detests in America following the September 11 attacks is one that seeks to reclaim a time that no longer exists. The security and confidence of the past is gone and in its place is a war where the enemy could be "anywhere." This changes the world as it provides the basis for continual suspicion, high levels of alert, and vigilance that precludes any form of trust or real understanding.
The world that Hamid depicts is one of perpetual antagonism. The ending of the novel is not one that openly embraces differences, but rather presents itself as one where there is mistrust in the world. The American does not fully know Changez's intent. Changez has judged the American in a manner that might not be fully accurate. Even this misereading of people applies to the personal realm. Erica cannot see Changez for what he is, but rather for what could be in the past. Even Changez is willing to subjugate his own identity for Erica in sex, but realizes that a world in which continual mistrust of one's identity is not sustainable. It is here in which the world that Hamid shows in the wake of September 11 is one where individuals cannot see one another for what they are, but rather for what they represent. It is in this element where the world has changed.