What is the significance of the final passage in "Araby" by James Joyce?

The final passage of James Joyce's "Araby" explains the epiphany the narrator had as a young boy that "vanity" caused him to believe his feelings mattered in the world. The young boy had been keenly aware of the little light in the overwhelmingly dark world he inhabits; when he plays outside in the dark, his body "glowed," and Mangan's sister is always "defined by the light" or "lit up" in some way. This light seems to be representative of his hope that Mangan's sister could return his love for her. When the boy is on his way to Araby, he notices only the lights "glaring with gas," the "twinkling river," and even the "lighted dial of a clock."  Araby is mostly dark when he arrives, however, and he realizes he has arrived too late. The boy was delayed by his uncle, his need for money, the terribly slow train, and his desire to locate a cheap entrance so that he could save his money to buy Mangan's sister a gift. He then discovers there is nothing worth purchasing anyway, and the remaining lights go out. Now in darkness, the narrator realizes his feelings for Mangan's sister do not matter to anyone or anything but him, and he loses his innocent hopefulness.