How does the setting contribute to the story?

In order to understand the contribution of the setting to the story, we should begin by looking at our main character, Wakefield. The narrator of the story asks, "What sort of a man was Wakefield?" He then goes on to describe a rather lackluster and middle-aged man. We then see further evidence of his mediocrity when the narrator states, "Had his acquaintances been asked, who was the man in London the surest to perform nothing today which should be remembered on the morrow, they would have thought of Wakefield." Wakefield puts on his coat and hat, smiles to his wife, and leaves. Having received no information to believe otherwise, his wife believes he'll return soon. His return, however, is twenty years later.
Now that we have some information on our main character, we'll look at the setting. The story takes place in busy London. When Wakefield leaves, the narrator warns the reader that we should follow our character, "ere he lose his individuality, and melt into the great mass of London life." Consider the streets of a bustling city with crowds of people. London is even referred to as being "busy and selfish." It is interesting to note here that our character risks losing what makes him different by blending in to the crowd. That is exactly what happens. Wakefield remains unnoticed for twenty years, living one street away from his wife. At one point in the story, the narrator tells of Wakefield's chance encounter with his wife. The city that allows him to remain hidden in its throngs of people, is the same city that forces them into this chance encounter. In this way, the setting contributes to the story. Our character is able to participate in his journey because the city enables him to do so.