Chicago's Brick

From D'Ambrosio's essay, I assume that there are many brick buildings in Chicago and that brick walls are very descriptive of the setting. I thought that D'Ambrosio imbued different meanings to bricks in his essay but one meaning that stood out the most for me was time. In the rapidly changing Chicago and passage of Chicago's numerous histories, such as the gambling, George, and Star Hotel, the author placed bricks as symbols for a constant entity. The bricks represent history, or bygone times of both the city and the author.
In the last paragraph the author mentions that he was gambling to salvage the past. I thought gambling was the opposite of bricks, in that gambling represents an event that does not last long or is unreliable and futile.
I thought the essay was very heavy and nostalgic, so it's hard to pinpoint the meaning of bricks, since bricks were so central to the story.