But it crumbled. The lifestyle of luxury could not be maintained after the Civil War. In the timeline of the novel, the culture falters almost immediately. All the eligible young men are off to war, and the rest of society is left to fend as best they can.
Fending gets harder and harder. But for the people caught in the nightmare, there is a sustaining thought: how very good they used to have it. The possibility of having it that good again fades further and further beyond reach. The Southern gentry are left without the gorgeous dresses. They salvage what they can. If they can't be rich and waited upon by scores of servants, at least they will maintain the morays and propriety.
Her friends and family cling to the memories. Scarlett, however, knows what she wants. Propriety was never that interesting to her; she wants the dresses back. She succeeds, but in the end discovers that her heartlessness has a cost.
Mitchell wrote about the origin of the customs of the South because she learned them growing up in Georgia. The customs were cherished and passed down with fondness. There is a romantic nostalgia for the plantation life that still lingers on for many. Mitchell learned from people who lived through the hard times of the war and the aftermath.
Now I come to my second perspective on the book: the times that the first readers were living through. Mitchell was born in 1900. She was in her 20s during the roaring 20s. When the Depression arrived, she felt all the lack of her former times. When Black Tuesday hit in 1929, all of America got a chance to feel the grinding hardship of survival. And pretty much everybody knew what it was like to be nostalgic for better times.
When Gone With the Wind came outin 1936, the Depression had been going on for 7 long years. It is easy to see how the story of Scarlett, belle of the county but reduced to scrambling for food in the ground and vowing "I will never be hungry again!", would resonate with the people who watched the hobos and maybe stood in the soup lines.