Changez's fate is to live the American Dream in a reverse kind of motion. Whereas most narratives of the American Dream begin with difficulty and drama and end with a sense of resolution about one's place in America, Changez goes in the opposite direction. His fate is to be one in which he experiences the prosperity and success of America at the start of his narrative, only to realize that this belies the fact that he really does not feel he has a place in America towards the end of it. Regardless of how one feels about the ending, it becomes clear that Changez has a very challenging and complex relationship between he and America. He is unable to fully shed that part of his identity. He will always, to a certain extent, have one foot of his consciousness in America. Even as a lecturer, Changez makes sure that he is focused on America as a target of his teachings. Here too, one can see that Changez is driven by the construction of America, albeit in the different way from the start of the narrative. Changez's fate is to be focused on America from a distance, so that no matter what he does or where he goes, he will always have America in his vision. It is here where the traditional focus and drive of the fundamentalist as one with a singular vision is replaced by the focus of one that is both driven by America and against it, simultaneously. It is here where Changez lives out the fate of the reluctant fundamentalist.
I wonder if I missed something, but I don't recall that Changez mentions belonging to a mosque, practicing the five pillars, or interacting with Muslims while he is in the United States. He decided to return to Pakistan to teach, encourage political activism, and practice Islam. I don't understand how any of that makes him a fundamentalist.